Experimental datasets on engineering properties of expansive soil treated with common salt.

PubMed

Durotoye, Taiwo O; Akinmusuru, Joseph O; Ogundipe, Kunle E

2018-06-01

Construction of highway pavements or high rise structures over the expansive soils are always problematic due to failures of volume change or swelling characteristic experienced in the water permeability of the soil. The data in this article represented summary of (Durotoye et al., 2016; Durotoye, 2016) [1], [2]. The data explored different percentages of sodium chloride as additive in stabilizing the engineering properties of expansive soil compared with other available stabilizer previously worked on. Experimental procedures carried out on expansive soil include: (Liquid limit, Plastic limit, Plasticity index, Shrinkage limit, Specific gravity Free swell index and Optimum water content) to determine the swelling parameters and (maximum dry density, California bearing ratio and unconfined compressive strength) to determine the strength parameters. The results of the experiment were presented in pie charts.

Abiotic soil changes induced by engineered nanomaterials: A critical review.

PubMed

Dror, Ishai; Yaron, Bruno; Berkowitz, Brian

2015-10-01

A large number of research papers on the fate of engineered nanomaterials (ENMs) in the soil-water system have appeared in recent years, focusing on ENM transport, persistence and toxicological impact. It is clear from these publications that soil is a major sink for ENMs, and that only a small portion degrades or is mobilized further into groundwater. However, to date, very few studies have examined the impact of ENMs on the natural soil-subsurface matrix and its properties. Moreover, it is now well accepted that chemical contaminants are capable of changing soil properties either by inducing direct chemical or physical changes, or through indirect changes by, e.g., influencing biological activity that in turn modifies soil properties. Here, we review studies on the deposition, retention, and accumulation of ENMs in soil, indicative of the extent to which soil acts as a major sink of ENMs. We then examine evidence of how these retained particles lead to modification of surface properties, which are manifested by changes in the sorption capacity of soil for other (organic and inorganic) solutes, and by surface charges and composition different than the natural surfaces. Finally, we demonstrate how this results in physical and hydrological changes to soil properties, including hydraulic conductivity, swelling capacity and wettability. The overall picture revealed in this critical review sheds light on a perspective that has received little attention thus far. These aspects of soil change, due to exposure and subsequent accumulation of ENMs, may ultimately prove to be one of the most important impacts of ENM releases to the environment. Copyright © 2015 Elsevier B.V. All rights reserved.

USCS and the USDA Soil Classification System: Development of a Mapping Scheme

DTIC Science & Technology

2015-03-01

important to human daily living. A variety of disciplines (geology, agriculture, engineering, etc.) require a sys- tematic categorization of soil, detailing...it is often important to also con- sider parameters that indicate soil strength. Two important properties used for engineering-related problems are...that many textural clas- sification systems were developed to meet specifics needs. In agriculture, textural classification is used to determine crop

The Relationship of Physical Property Indicators and Clay Soil Structural Strength of Tomsk Oblast Territory

NASA Astrophysics Data System (ADS)

Kramarenko, V. V.; Nikitenkov, A. N.; Molokov, V. Y.; Matveenko, I. A.; Shramok, A. V.

2015-11-01

The article deals with the characteristic of initial condition in fine-grained soils - its structural strength - pstr. Estimation and measurement of this factor at soil testing are of primary importance for defining its physical and mechanical properties as well as for subsequent calculation of foundation settlements that is insufficiently covered in Code of practice, national standard and inefficiently applicable in practice of engineering geological investigations. The article reveals the relationship between soil physical property, its occurrence depth, which will make possible to forecast pstr over the given territory.

Evolution of black carbon properties in soil

USDA-ARS?s Scientific Manuscript database

Black carbon deposited in soil from natural or deliberate wildfires and engineered black carbon products (biochar) intentionally added to soil are known to have significant effects on soil biogeochemical processes and in many cases to influence the yield and quality of crops and to enhance the abili...

Structure and earthworms

USDA-ARS?s Scientific Manuscript database

Earthworms are an important part of the soil ecosystem and an indicator of soil quality. Sometimes referred to as ecosystem engineers, they play a pivotal role in maintaining soil productivity. Their burrowing, feeding, and casting activities alter the physical, chemical, and biological properties o...

Feasibility of biochar application on a landfill final cover-a review on balancing ecology and shallow slope stability.

PubMed

Chen, Xun-Wen; Wong, James Tsz-Fung; Ng, Charles Wang-Wai; Wong, Ming-Hung

2016-04-01

Due to the increasing concerns on global warming, scarce land for agriculture, and contamination impacts on human health, biochar application is being considered as one of the possible measures for carbon sequestration, promoting higher crop yield and contamination remediation. Significant amount of researches focusing on these three aspects have been conducted during recent years. Biochar as a soil amendment is effective in promoting plant performance and sustainability, by enhancing nutrient bioavailability, contaminants immobilization, and microbial activities. The features of biochar in changing soil physical and biochemical properties are essential in affecting the sustainability of an ecosystem. Most studies showed positive results and considered biochar application as an effective and promising measure for above-mentioned interests. Bio-engineered man-made filled slope and landfill slope increasingly draw the attention of geologists and geotechnical engineers. With increasing number of filled slopes, sustainability, low maintenance, and stability are the major concerns. Biochar as a soil amendment changes the key factors and parameters in ecology (plant development, soil microbial community, nutrient/contaminant cycling, etc.) and slope engineering (soil weight, internal friction angle and cohesion, etc.). This paper reviews the studies on the production, physical and biochemical properties of biochar and suggests the potential areas requiring study in balancing ecology and man-made filled slope and landfill cover engineering. Biochar-amended soil should be considered as a new type of soil in terms of soil mechanics. Biochar performance depends on soil and biochar type which imposes challenges to generalize the research outcomes. Aging process and ecotoxicity studies of biochar are strongly required.

[Effects of Cultivation Soil Properties on the Transport of Genetically Engineered Microorganism in Huabei Plain].

PubMed

Zhang, Jing; Liu, Ping; Liu, Chun; Chen, Xiao-xuan; Zhang, Lei

2015-12-01

The transport of genetically engineered microorganism (GEM) in the soil is considered to be the important factor influencing the enhanced bioremediation of polluted soil. The transport of an atrazine-degrading GEM and its influencing factors were investigated in the saturated cultivation soil of Huabei Plain. The results showed that horizontal infiltration was the main mechanism of GEM transport in the saturated cultivation soil. The transport process could be simulated using the filtration model. Soil properties showed significant effects on pore water flow and GEM transport in saturated soil. When particle size, porosity and sand component of the soil increased, the hydraulic conductivity constant increased and filtration coefficient of GEM decreased in saturated soil, indicating the reduced retention of GEM in the soil. An increase in infiltration flow also increased hydraulic conductivity constant in saturated soil and consequently decreased filtration coefficient of GEM. When hydraulic conductivity constants ranged from 5.02 m · d⁻¹ to 6.70 m · d⁻¹ in the saturated soil, the filtration coefficients of GEM varied from 0.105 to 0.274. There was a significantly negative correlation between them.

Assessing designer biochar characteristics to ameliorate specific soil limitations

EPA Science Inventory

It is widely recognized that not all biochars are equal in their ability to improve soil physical and chemical properties that influence soil health. Therefore, we are examining the potential of engineering biochars through feedstock, pyrolysis conditions, and particle size sele...

Enhancement of surfactant efficacy during the cleanup of engine oil contaminated soil using salt and multi-walled carbon nanotubes.

PubMed

Bonal, Niteesh Singh; Paramkusam, Bala Ramudu; Basudhar, Prabir Kumar

2018-06-05

The study aims to enhance the efficacy of surfactants using salt and multi-walled carbon nanotubes (MWCNT) for washing used engine oil (UEO) contaminated soil and compare the geotechnical properties of contaminated soil before and after washing (batch washing and soil washing). From batch washing of the contaminated soil the efficacy of the cleaning process is established. Contamination of soil with hydrocarbons present in UEO significantly affects its' engineering properties manifesting in no plasticity and low specific gravity; the corresponding optimum moisture content value is 6.42% while maximum dry density is 1.770 g/cc, which are considerably lower than those of the uncontaminated soil. The result also showed decrease in the values of cohesion intercept and increase in the friction angle values. The adopted soil washing technique resulted increase in specific gravity from 1.85 to 2.13 and cohesion from 0.443 to 1.04 kg/cm 2 and substantial decrease in the friction angle from 31.16° to 17.14° when washed with most efficient combination of SDS surfactant along with sodium meta-silicate (salt) and MWCNT. Effectiveness of the washing of contaminated soil by batch processing and soil washing techniques has been established qualitatively. The efficiency of surfactant treatment has been observed to be increased significantly by the addition of salt and MWCNT. Copyright © 2018 Elsevier B.V. All rights reserved.

Rich in life but poor in data: the known knowns and known unknowns of modelling how soil biology drives soil structure

NASA Astrophysics Data System (ADS)

Hallett, Paul; Ogden, Mike

2015-04-01

Soil biology has a fascinating capacity to manipulate pore structure by altering or overcoming hydrological and mechanical properties of soil. Many have postulated, quite rightly, that this capacity of soil biology to 'engineer' its habitat drives its diversity, improves competitiveness and increases resilience to external stresses. A large body of observational research has quantified pore structure evolution accompanied by the growth of organisms in soil. Specific compounds that are exuded by organisms or the biological structures they create have been isolated and found to correlate well with observed changes to pore structure or soil stability. This presentation will provide an overview of basic mechanical and hydrological properties of soil that are affected by biology, and consider missing data that are essential to model how they impact soil structure evolution. Major knowledge gaps that prevent progress will be identified and suggestions will be made of how research in this area should progress. We call for more research to gain a process based understanding of structure formation by biology, to complement observational studies of soil structure before and after imposed biological activity. Significant advancement has already been made in modelling soil stabilisation by plant roots, by combining data on root biomechanics, root-soil interactions and soil mechanical properties. Approaches for this work were developed from earlier materials science and geotechnical engineering research, and the same ethos should be adopted to model the impacts of other biological compounds. Fungal hyphae likely reinforce soils in a similar way to plant roots, with successful biomechanical measurements of these micron diameter structures achieved with micromechanical test frames. Extending root reinforcement models to fungi would not be a straightforward exercise, however, as interparticle bonding and changes to pore water caused by fungal exudates could have a major impact on structure formation and stability. Biological exudates from fungi, bacteria or roots have been found to decrease surface tension and increase viscosity of pore water, with observed impacts to soil strength and water retention. Modelling approaches developed in granular mechanics and geotechnical engineering could be built upon to incorporate biological transformations of hydrological and mechanical properties of soil. With new testing approaches, adapted from materials science, pore scale hydromechanical impacts from biological exudates can be quantified. The research can be complemented with model organisms with differences in biological structures (e.g. root hair mutants), exudation or other properties. Coupled with technological advances that provide 4D imaging of soil structure at relatively rapid capture rates, the potential opportunities to disentangle and model how biology drives soil structure evolution and stability are vast. By quantifying basic soil hydrological and mechanical processes that are driven by soil biology, unknown unknowns may also emerge, providing new insight into how soils function.

Earthworms as ecosystem engineers and the most important detritivors in forest soils.

PubMed

Kooch, Yahya; Jalilvand, Hamid

2008-03-15

Earthworms are considered as soil engineers because of their effects on soil properties and their influence on the availability of resources for other organisms, including microorganisms and plants. However, the links between their impacts on the soil environment and the resulting modification of natural selection pressures on engineer as well as on other organisms have received little attention. Earthworms are known to have a positive influence on the soil fabric and on the decomposition and mineralization of litter by breaking down organic matter and producing large amounts of fasces, thereby mixing litter with the mineral soil. Therefore, they play an important part in changes from one humus from to another according to forest succession patterns. Consequently, they are also expected to be good bio-indicators for forest site quality and are thus useful when planning forest production improvement. Earthworm's populations are as indicator that in exploited regions is destruction indicator and reclamation plans is nature return indicator. In this study we summarized the current knowledge in relation to earthworm's ecology in forest soils as ecosystem engineers.

[Time-evolution study on the cation exchange in the process of reinforcing slip soil by laser-induced breakdown spectroscopy].

PubMed

Liu, Lu-Wen; Zeng, Wei-Li; Zhu, Xiang-Fei; Wu, Jin-Quan; Lin, Zhao-Xiang

2014-03-01

In the present paper, the time evolution study on slip soils treated by different proportions of ionic soil stabilizer (ISS) water solution was conducted by the LIBS system and the relationship between the cation exchange and such engineering properties of reinforcing soil as plasticity index, cohesive force and coefficient of compressibility were analyzed. The results showed that the cation exchange velocity of the proportion of 1:200 ISS reinforcing soil is the fastest among the three proportions (1:100, 1:200 and 1:300) and the modification effect of engineering performance index is quite obvious. These studies provide an experimental basis for the ISS applied to curing project, and monitoring geotechnical engineering performance by LIBS technology also provides a new way of thinking for the curing project monitoring.

JMSS-1: a new Martian soil simulant

NASA Astrophysics Data System (ADS)

Zeng, Xiaojia; Li, Xiongyao; Wang, Shijie; Li, Shijie; Spring, Nicole; Tang, Hong; Li, Yang; Feng, Junming

2015-05-01

It is important to develop Martian soil simulants that can be used in Mars exploration programs and Mars research. A new Martian soil simulant, called Jining Martian Soil Simulant (JMSS-1), was developed at the Lunar and Planetary Science Research Center at the Institute of Geochemistry, Chinese Academy of Sciences. The raw materials of JMSS-1 are Jining basalt and Fe oxides (magnetite and hematite). JMSS-1 was produced by mechanically crushing Jining basalt with the addition of small amounts of magnetite and hematite. The properties of this simulant, including chemical composition, mineralogy, particle size, mechanical properties, reflectance spectra, dielectric properties, volatile content, and hygroscopicity, have been analyzed. On the basis of these test results, it was demonstrated that JMSS-1 is an ideal Martian soil simulant in terms of chemical composition, mineralogy, and physical properties. JMSS-1 would be an appropriate choice as a Martian soil simulant in scientific and engineering experiments in China's Mars exploration in the future.

Soil fauna, soil properties and geo-ecosystem functioning

NASA Astrophysics Data System (ADS)

Cammeraat, L. H.

2012-04-01

The impact of soil fauna on soil processes is of utmost importance, as the activity of soil fauna directly affects soil quality. This is expressed by the direct effects of soil fauna on soil physical and soil chemical properties that not only have great importance to food production and ecosystems services, but also on weathering and hydrological and geomorphological processes. Soil animals can be perceived as ecosystem engineers that directly affect the flow of water, sediments and nutrients through terrestrial ecosystems. The biodiversity of animals living in the soil is huge and shows a huge range in size, functions and effects. Most work has been focused on only a few species such as earthworms and termites, but in general the knowledge on the effect of soil biota on soil ecosystem functioning is limited as it is for their impact on processes in the soil and on the soil surface. In this presentation we would like to review some of the impacts of soil fauna on soil properties that have implications for geo-ecosystem functioning and soil formation processes.

Control of embankment settlement field verification on PCPT prediction methods.

DOT National Transportation Integrated Search

2011-07-01

Piezocone penetration tests (PCPT) have been widely used by geotechnical engineers for subsurface investigation and evaluation of different soil properties such as strength and deformation characteristics of the soil. This report focuses on the verif...

Control of embankment settlement field verification on PCPT prediction methods.

DOT National Transportation Integrated Search

2011-07-01

Piezocone penetration tests (PCPT) have been widely used by geotechnical engineers for subsurface : investigation and evaluation of different soil properties such as strength and deformation characteristics of the : soil. This report focuses on the v...

Geotechnical Materials Database for Embankment Design and Construction

DOT National Transportation Integrated Search

2011-12-01

This project was focused on the assimilation of engineering properties of borrow soils across the state of : South Carolina. Extensive data on soils used for embankment construction were evaluated and compared : within Group A (Piedmont) and Group B ...

Biofuel co-product uses for pavement geo-materials stabilization : tech transfer summary, April 2010.

DOT National Transportation Integrated Search

2010-04-01

Objectives : Evaluate the ability of biofuel co-product (BCP) to function as an effective soil stabilizing agent. : Investigate the effect of BCP on the engineering properties of soil-BCP mixtures for Iowa conditions.

Measuring in situ mechanical properties of pavement subgrade soils

DOT National Transportation Integrated Search

1999-01-01

This synthesis report will be of interest to pavement and geotechnical design and research engineers, geologists and engineering geologists, and similar laboratory personnel. It describes the current practice for measuring the in situ mechanical prop...

Effects on soils from hot storage tanks

NASA Astrophysics Data System (ADS)

Ko, K. C.

1982-02-01

Behavioral characteristics of foundation soils for hot storage tanks were investigated on two soil models representative of the soils in the Continental U.S. The changes in the engineering properties of the foundation soils due to heating and the effects of four storage media liquids; hydrocarbon oil, silicon oil, molten nitrate salt and liquid sodium into the foundation were investigated. The remedial measures such as soil preconditioning to alleviate the detrimental effects of the heat on soils are presented and the areas for further research are delineated.

Soil Texture Estimates: A Tool to Compare Texture-by-Feel and Lab Data

ERIC Educational Resources Information Center

Franzmeier, D.P.; Owens, P.R.

2008-01-01

Soil texture is a fundamental soil property that impacts agricultural and engineering land-use. Comparing texture estimates-by-feel to laboratory-known values to calibrate fingers is a common practice. As educators, it is difficult to assess this field skill consistently and fairly. The instructor may give full credit for the correct texture class…

Improvement in engineering properties of soft-soil using cement and lime additives: A case study of southern Vietnam

NASA Astrophysics Data System (ADS)

To-Anh Phan, Vu; Ngoc-Anh Pham, Kha

2018-04-01

This paper presents the experimental results of using two additives to improve natural soft soil properties in southern Vietnam (i.g., cement and cement-lime mixture). The specimens were prepared by compacting method. Firstly, the natural soil was mixed with cement or cement-lime to determine the optimum water contents of various additive contents. Then, optimum water content was used to produce samples to test some engineering properties such as unconfined compressive strength, splitting tensile strength, and Young’s modulus. The specimens were tested by various curing duration of 7, 14, and 28 days. Results indicated that using cement additive is suitable for improvement of soft soil in the local area and cement-soil stabilization can be replaced as the subbase layer of the flexible pavement according to current Vietnamese standard. In addition, a higher cement content has a greater compressive strength as well as tensile strength. Besides, the Young’ modulus has significantly increased with a long-term curing age and more cement content. No evidences of increasing in strength and modulus are found with the cement-lime-soil stabilization. Finally, the best-fit power function is established by the relationships between unconfined compressive strength and splitting tensile strength as well unconfined compressive strength and Young’s Modulus, with the coefficient of determination, R2>0.999.

Effects of soil-engineering properties on the failure mode of shallow landslides

USGS Publications Warehouse

McKenna, Jonathan Peter; Santi, Paul Michael; Amblard, Xavier; Negri, Jacquelyn

2012-01-01

Some landslides mobilize into flows, while others slide and deposit material immediately down slope. An index based on initial dry density and fine-grained content of soil predicted failure mode of 96 landslide initiation sites in Oregon and Colorado with 79% accuracy. These material properties can be used to identify potential sources for debris flows and for slides. Field data suggest that loose soils can evolve from dense soils that dilate upon shearing. The method presented herein to predict failure mode is most applicable for shallow (depth 8), with few to moderate fines (fine-grained content <18%), and with liquid limits <40.

Reuse of coal mining wastes in civil engineering. Part 1: Properties of minestone

DOE Office of Scientific and Technical Information (OSTI.GOV)

Skarzynska, K.M.

1995-07-01

This review is intended to introduce the readers to the geotechnical properties of minestone obtained from various countries and to describe laboratory and field methods used to examine and evaluate such material. The contents of the paper consist of general information on the environmental consequences of coal mining, the origin of the by-product, and the classification of the material. Primary emphasis has been placed on describing the physical and mechanical properties with respect to geotechnical engineering. Characteristic properties, such as degradation, weathering, spontaneous heating, etc., are specific for this man-made soil and are discussed in relationship to civil engineering. Finally,more » the current and far-reaching effects of existing radioactivity is also presented. Preparation of the review is based on an extensive literature survey, as well as on the investigations of the author and practical applications. A general conclusion can be made from the reviewed data that a noticeable similarity does exist between the chemical, physical, and mechanical properties of minestone from different sources and countries. this is important because the research results and practical experience obtained in one country may then be applied to projects in another country. The review should be helpful in understanding the behavior of minestone during its transport for prospective utilization in different engineering projects. The author hopes that the information will be useful to those studying environmental, civil, and water engineering, as well as for designers and researchers investigating the potential use of this man-made (anthropogenic) soil in various fields of engineering.« less

Fiber reinforced sandy slopes under groundwater return flow

USDA-ARS?s Scientific Manuscript database

The instability of natural hillslopes, riverbanks and engineered embankments due to seepage has been a major concern. In an effort to prevent failures, tension resisting synthetic fibers may be an effective additive to increase the mechanical properties of engineered soils. In this study, triaxial c...

Rice husk ash (RHA) as a partial cement replacement in modifying peat soil properties

NASA Astrophysics Data System (ADS)

Daud, Nik Norsyahariati Nik; Daud, Mohd Nazrin Mohd; Muhammed, Abubakar Sadiq

2018-02-01

This paper describes the effect of rice husk ash (RHA) and ordinary Portland cement (OPC) as a potential binder for modifying the properties of peat soil. The amounts RHA and OPC added to the peat soil sample, as percentage of the dry soil mass were in the range of 10-15% and 15%, respectively. Observations were made for the changes in the properties of the soil such as maximum dry density (MDD), optimum moisture content (OMC) and shear strength. Scanning Electron Micrograph-Energy Dispersive X-Ray (SEM-EDX) test were also conducted to observe the microstructure of treated and untreated peat soil. The results show that the modified soil of MDD and OMC values are increased due to the increment amount of binder material. Shear strength values of modified peat showing a good result by assuming that it is relative to the formation of major reaction products such as calcium silicate hydrate (C-S-H). The presence of C-S-H formation is indicated by the results produced from microstructural analysis of peat before and after modification process. This depicts the potential usage of RHA as a partial cement replacement in peat soil which is also improving its engineering properties.

Application of geotechnical data to resource planning in southeast Alaska.

Treesearch

W.L. Schroeder; D.N. Swanston

1987-01-01

Recent quantification of engineering properties and index values of dominant soil types in the Alexander Archipelago, southeast Alaska, have revealed consistent diagnostic characteristics useful to evaluating landslide risk and subgrade material stability before timber harvesting and low-volume road construction. Shear strength data are summarized and grouped by Soil...

Decision Tree Approach for Soil Liquefaction Assessment

PubMed Central

Gandomi, Amir H.; Fridline, Mark M.; Roke, David A.

2013-01-01

In the current study, the performances of some decision tree (DT) techniques are evaluated for postearthquake soil liquefaction assessment. A database containing 620 records of seismic parameters and soil properties is used in this study. Three decision tree techniques are used here in two different ways, considering statistical and engineering points of view, to develop decision rules. The DT results are compared to the logistic regression (LR) model. The results of this study indicate that the DTs not only successfully predict liquefaction but they can also outperform the LR model. The best DT models are interpreted and evaluated based on an engineering point of view. PMID:24489498

Decision tree approach for soil liquefaction assessment.

PubMed

Gandomi, Amir H; Fridline, Mark M; Roke, David A

2013-01-01

In the current study, the performances of some decision tree (DT) techniques are evaluated for postearthquake soil liquefaction assessment. A database containing 620 records of seismic parameters and soil properties is used in this study. Three decision tree techniques are used here in two different ways, considering statistical and engineering points of view, to develop decision rules. The DT results are compared to the logistic regression (LR) model. The results of this study indicate that the DTs not only successfully predict liquefaction but they can also outperform the LR model. The best DT models are interpreted and evaluated based on an engineering point of view.

Constitutive and Stability Behavior of Soils in Microgravity Environment

NASA Technical Reports Server (NTRS)

Alshibli, Khalid A.; Sture, Stein; Costes, Nicholas

2000-01-01

All aspects of soil stability, bearing capacity, slope stability, the supporting capacity of deep foundations, and penetration resistance depend on soil strength. The stress-deformation and stress-deformation-time behavior of soils are of importance in any problem where ground movements are of interest. In most engineering materials, the strength is derived from internal chemical and physico-chemical forces of interaction, which bond the atoms, molecules, and particles together. In soils, the constitutive relations are mainly derived from interparticle friction between particles and particle groups and dilatancy, and to a lesser extent from particle bonding by weak electrostatic, physico-chemical, and coulomb forces. For engineering purposes, soils are classified as cohesive (clays and silts; typical particle sizes range from 10 nm to 10 micrometers) and cohesionless (sand and gravel; typical particle sizes range from 10 micrometers to 75 mm). The mechanical or constitutive properties of cohesionless soils or granular materials are highly fabric-dependent, highly non-linear, and non-conservative with engineering properties primarily depending on the effects of gravity through self-weight and on the tractions or forces applied to the soil mass. Under moderate-to-high stress levels, the influence of gravity on the behavior of laboratory test specimens may not be pronounced and, therefore, the test results in terrestrial (1-g) environment may be sufficiently conclusive. However at low interparticle stresses, which can result either from low applied (confining) stresses or from excess pore fluid pressures developed within the soil mass without corresponding changes in the applied stresses, the presence of gravitational body forces acting on solid particles and interstitial fluids exerts a pronounced influence on movement of individual particles or particle groups. Such motions, in turn, cause changes in soil fabric which results in significant changes in the interparticle friction forces contributing to the soil's strength and deformation characteristics.

Geological and engineering analysis of residual soil for forewarning landslide from highland area in northern Thailand

NASA Astrophysics Data System (ADS)

Thongkhao, Thanakrit; Phantuwongraj, Sumet; Choowong, Montri; Thitimakorn, Thanop; Charusiri, Punya

2015-11-01

One devastating landslide event in northern Thailand occurred in 2006 at Ban Nong Pla village, Chiang Klang highland of Nan province after, a massive amount of residual soil moved from upstream to downstream, via creek tributaries, into a main stream after five days of unusual heavy rainfall. In this paper, the geological and engineering properties of residual soil derived fromsedimentary rocks were analyzed and integrated. Geological mapping, electrical resistivity survey and test pits were carried out along three transect lines together with systematic collection of undisturbed and disturbed residual soil samples. As a result, the average moisture content in soil is 24.83% with average specific gravity of 2.68,whereas the liquid limit is 44.93%, plastic limit is 29.35% and plastic index is 15.58%. The cohesion of soil ranges between 0.096- 1.196 ksc and the angle of internal friction is between 11.51 and 35.78 degrees. This suggests that the toughness properties of soil change when moisture content increases. Results from electrical resistivity survey reveal that soil thicknesses above the bedrock along three transects range from 2 to 9 m. The soil shear strength reach the rate of high decreases in the range of 72 to 95.6% for residual soil from shale, siltstone and sandstone, respectively. Strength of soil decreaseswhen the moisture content in soil increases. Shear strength also decreases when the moisture content changes. Therefore, the natural soil slope in the study area will be stable when the moisture content in soil level is equal to one, but when the moisture content between soil particle increases, strength of soil will decrease resulting in soil strength decreasing.

Effect of Ionic Soil Stabilizers on Soil-Water Characteristic of Special Clay

NASA Astrophysics Data System (ADS)

Cui, D.; Xiang, W.

2011-12-01

The engineering properties of special clay are conventionally improved through the use of chemical additive such as ionic soil stabilizer (ISS). Such special clays are often referred to as stabilized or treated clays. The soil-water characteristic curves (SWCC) of special clays from Henan province and Hubei province were measured both in natural and stabilized conditions using the pressure plate apparatus in the suction range of 0-500 kPa. The SWCC results are used to interpret the special clays behavior due to stabilizer treatment. In addition, relationships were developed between the basic clay and stabilized properties such as specific surface area and pore size distribution. The analysis showed that specific surface area decreases, cumulative pore volume and average pore size diameter decrease, dehydration rate slows and the thickness of water film thins after treatment with Ionic Soil Stabilizer. The research data and interpretation analysis presented here can be extended to understand the water film change behaviors influencing the mechanical and physical properties of stabilized special clay soils. KEY WORDS: ionic soil stabilizer, special clay, pore size diameter, specific surface area, soil water characteristic curve, water film

Biofilm effect on soil hydraulic properties: Experimental investigation using soil-grown real biofilm

NASA Astrophysics Data System (ADS)

Volk, Elazar; Iden, Sascha C.; Furman, Alex; Durner, Wolfgang; Rosenzweig, Ravid

2016-08-01

Understanding the influence of attached microbial biomass on water flow in variably saturated soils is crucial for many engineered flow systems. So far, the investigation of the effects of microbial biomass has been mainly limited to water-saturated systems. We have assessed the influence of biofilms on the soil hydraulic properties under variably saturated conditions. A sandy soil was incubated with Pseudomonas Putida and the hydraulic properties of the incubated soil were determined by a combination of methods. Our results show a stronger soil water retention in the inoculated soil as compared to the control. The increase in volumetric water content reaches approximately 0.015 cm3 cm-3 but is only moderately correlated with the carbon deficit, a proxy for biofilm quantity, and less with the cell viable counts. The presence of biofilm reduced the saturated hydraulic conductivity of the soil by up to one order of magnitude. Under unsaturated conditions, the hydraulic conductivity was only reduced by a factor of four. This means that relative water conductance in biofilm-affected soils is higher compared to the clean soil at low water contents, and that the unsaturated hydraulic conductivity curve of biofilm-affected soil cannot be predicted by simply scaling the saturated hydraulic conductivity. A flexible parameterization of the soil hydraulic functions accounting for capillary and noncapillary flow was needed to adequately describe the observed properties over the entire wetness range. More research is needed to address the exact flow mechanisms in biofilm-affected, unsaturated soil and how they are related to effective system properties.

Mechanical properties of lunar regolith and lunar soil simulant

NASA Technical Reports Server (NTRS)

Perkins, Steven W.

1989-01-01

Through the Surveyor 3 and 7, and Apollo 11-17 missions a knowledge of the mechanical properties of Lunar regolith were gained. These properties, including material cohesion, friction, in-situ density, grain-size distribution and shape, and porosity, were determined by indirect means of trenching, penetration, and vane shear testing. Several of these properties were shown to be significantly different from those of terrestrial soils, such as an interlocking cohesion and tensile strength formed in the absence of moisture and particle cementation. To characterize the strength and deformation properties of Lunar regolith experiments have been conducted on a lunar soil simulant at various initial densities, fabric arrangements, and composition. These experiments included conventional triaxial compression and extension, direct tension, and combined tension-shear. Experiments have been conducted at low levels of effective confining stress. External conditions such as membrane induced confining stresses, end platten friction and material self weight have been shown to have a dramatic effect on the strength properties at low levels of confining stress. The solution has been to treat these external conditions and the specimen as a full-fledged boundary value problem rather than the idealized elemental cube of mechanics. Centrifuge modeling allows for the study of Lunar soil-structure interaction problems. In recent years centrifuge modeling has become an important tool for modeling processes that are dominated by gravity and for verifying analysis procedures and studying deformation and failure modes. Centrifuge modeling is well established for terrestrial enginering and applies equally as well to Lunar engineering. A brief review of the experiments is presented in graphic and outline form.

Calculation and analysis on bolts on the slope of Xigeda soil

NASA Astrophysics Data System (ADS)

Wang, Wei; Chen, Wei; Long, Wei; Die, Jian

2018-03-01

In this paper, the commonly-used full-length bonded bolt in Xigeda soil and its slope support engineering is taken as the research object, applying the mechanical property indicator of Xigeda soil and two existing bolt load transmission mechanism and calculation theory, so that two calculation formulas of anchoring forces can be deduced, and verified by the experimental data. This paper has certain practical significance.

Effect of aggregation on SOC transport: linking soil properties to sediment organic matter

NASA Astrophysics Data System (ADS)

Kuhn, Nikolaus J.

2016-04-01

Soils are an interface between the Earth's spheres and shaped by the nature of the interaction between them. The relevance of soil properties for the nature of the interaction between atmosphere, hydrosphere and biosphere is well-studied and accepted, on point- or ecotone-scale. However, this understanding of the largely vertical connections between spheres is not matched by a similar recognition of soil properties affecting processes acting largely in a lateral way across the land surface, such as erosion, transport and deposition of soil and the associated organic matter. Understanding the redistribution of eroded soil organic matter falls into several disciplines, most notably soil science, agronomy, hydrology and geomorphology, and recently into biogeochemistry. Accordingly, the way soil and sediment are described differs: in soil science, aggregation and structure are essential properties, while most process-based soil erosion models treat soil as a mixture of individual mineral grains, based on concepts derived in fluvial geomorphology or civil engineering. The actual behavior of aggregated sediment and the associated organic matter is not reflected by either approach and difficult to capture due to the dynamic nature of aggregation, especially in an environment such as running water. Still, a proxy to assess the uncertainties introduced by aggregation on the behavior of soil/sediment organic while moving in water across landscapes and into the aquatic system would represent a major step forward. To develop such a proxy, a database collating relevant soil, organic matter and sediment properties could serve as an initial step to identify which soil types and erosion scenarios are prone to generate a high uncertainty compared to the use of soil texture in erosion models. Furthermore, it could serve to develop standardized analytical procedures for appropriate description of soil and organic matter as sediment.

Fundamental Properties of Soils for Complex Dynamic Loadings: Dynamic Constitutive Modeling of Sandy Soils.

DTIC Science & Technology

1983-04-01

1.0 INTRODUCTION AND SCOPE 1 2.0 PROGRESS SUMMARY 3 2.1 Soil Element Model Development 3 2.2 U.S. Any Engineer Waterways Experiment Station (WES...LABORATORY BEHAVIOR OF SAND 8 3.1 Introduction 8 3.2 Material Description 8 3.3 Laboratory Tests Performed 9 3.4 Laboratory Test Results 14 4.0 MODELING THE... INTRODUCTION AND SCOPE The subject of this annual report is constitutive modeling of cohesionless soil, for both laboratory standard static test conditions

Clay stabilization by using gypsum and paddy husk ash with reference to UCT and CBR value

NASA Astrophysics Data System (ADS)

Roesyanto; Iskandar, R.; Hastuty, I. P.; Dianty, W. O.

2018-02-01

Clays that have low shear strength need to be stabilized in order to meet the technical requirements to serve as a subgrade material. One of the usual soil stabilization methods is by adding chemicals such as Portland cement, lime, and bitumen. The clay stabilization research was done by adding gypsum and paddy husk ash. The research goals were to find out the value of engineering properties of clay due to the addition of 2% gypsum and 2% - 15% paddy husk ash. The soil was classified as Clay - Low Plasticity (CL) based on USCS and was classified as A-7-6 (10) based on AASHTO classification system. The UCT value of original soil was 1.41 kg/cm2. While the CBR soaked and unsoaked values of original soil were 4.41% and 6.23% respectively. The research results showed the addition of paddy husk ash decreased the value of unconfined compressive strength as well as CBR. The stabilized soil by 2% gypsum and 0% paddy husk ash gave maximum UCT value of 1.67 kg/cm2, while the maximum value of CBR were found 6.71% for CBR soaked and 8.00% for CBR unsoaked. The addition of paddy husk ash did not alter the soil classification according to AASHTO or USCS, even degrade the engineering properties of original soil.

Soil variability in engineering applications

NASA Astrophysics Data System (ADS)

Vessia, Giovanna

2014-05-01

Natural geomaterials, as soils and rocks, show spatial variability and heterogeneity of physical and mechanical properties. They can be measured by in field and laboratory testing. The heterogeneity concerns different values of litho-technical parameters pertaining similar lithological units placed close to each other. On the contrary, the variability is inherent to the formation and evolution processes experienced by each geological units (homogeneous geomaterials on average) and captured as a spatial structure of fluctuation of physical property values about their mean trend, e.g. the unit weight, the hydraulic permeability, the friction angle, the cohesion, among others. The preceding spatial variations shall be managed by engineering models to accomplish reliable designing of structures and infrastructures. Materon (1962) introduced the Geostatistics as the most comprehensive tool to manage spatial correlation of parameter measures used in a wide range of earth science applications. In the field of the engineering geology, Vanmarcke (1977) developed the first pioneering attempts to describe and manage the inherent variability in geomaterials although Terzaghi (1943) already highlighted that spatial fluctuations of physical and mechanical parameters used in geotechnical designing cannot be neglected. A few years later, Mandelbrot (1983) and Turcotte (1986) interpreted the internal arrangement of geomaterial according to Fractal Theory. In the same years, Vanmarcke (1983) proposed the Random Field Theory providing mathematical tools to deal with inherent variability of each geological units or stratigraphic succession that can be resembled as one material. In this approach, measurement fluctuations of physical parameters are interpreted through the spatial variability structure consisting in the correlation function and the scale of fluctuation. Fenton and Griffiths (1992) combined random field simulation with the finite element method to produce the Random Finite Element Method (RFEM). This method has been used to investigate the random behavior of soils in the context of a variety of classical geotechnical problems. Afterward, some following studies collected the worldwide variability values of many technical parameters of soils (Phoon and Kulhawy 1999a) and their spatial correlation functions (Phoon and Kulhawy 1999b). In Italy, Cherubini et al. (2007) calculated the spatial variability structure of sandy and clayey soils from the standard cone penetration test readings. The large extent of the worldwide measured spatial variability of soils and rocks heavily affects the reliability of geotechnical designing as well as other uncertainties introduced by testing devices and engineering models. So far, several methods have been provided to deal with the preceding sources of uncertainties in engineering designing models (e.g. First Order Reliability Method, Second Order Reliability Method, Response Surface Method, High Dimensional Model Representation, etc.). Nowadays, the efforts in this field have been focusing on (1) measuring spatial variability of different rocks and soils and (2) developing numerical models that take into account the spatial variability as additional physical variable. References Cherubini C., Vessia G. and Pula W. 2007. Statistical soil characterization of Italian sites for reliability analyses. Proc. 2nd Int. Workshop. on Characterization and Engineering Properties of Natural Soils, 3-4: 2681-2706. Griffiths D.V. and Fenton G.A. 1993. Seepage beneath water retaining structures founded on spatially random soil, Géotechnique, 43(6): 577-587. Mandelbrot B.B. 1983. The Fractal Geometry of Nature. San Francisco: W H Freeman. Matheron G. 1962. Traité de Géostatistique appliquée. Tome 1, Editions Technip, Paris, 334 p. Phoon K.K. and Kulhawy F.H. 1999a. Characterization of geotechnical variability. Can Geotech J, 36(4): 612-624. Phoon K.K. and Kulhawy F.H. 1999b. Evaluation of geotechnical property variability. Can Geotech J, 36(4): 625-639. Terzaghi K. 1943. Theoretical Soil Mechanics. New York: John Wiley and Sons. Turcotte D.L. 1986. Fractals and fragmentation. J Geophys Res, 91: 1921-1926. Vanmarcke E.H. 1977. Probabilistic modeling of soil profiles. J Geotech Eng Div, ASCE, 103: 1227-1246. Vanmarcke E.H. 1983. Random fields: analysis and synthesis. MIT Press, Cambridge.

The Influence of Basic Physical Properties of Soil on its Electrical Resistivity Value under Loose and Dense Condition

NASA Astrophysics Data System (ADS)

Abidin, M. H. Z.; Ahmad, F.; Wijeyesekera, D. C.; Saad, R.

2014-04-01

Electrical resistivity technique has become a famous alternative tool in subsurface characterization. In the past, several interpretations of electrical resistivity results were unable to be delivered in a strong justification due to lack of appreciation of soil mechanics. Traditionally, interpreters will come out with different conclusion which commonly from qualitative point of view thus creating some uncertainty regarding the result reliability. Most engineers desire to apply any techniques in their project which are able to provide some clear justification with strong, reliable and meaningful results. In order to reduce the problem, this study presents the influence of basic physical properties of soil due to the electrical resistivity value under loose and dense condition. Two different conditions of soil embankment model were tested under electrical resistivity test and basic geotechnical test. It was found that the electrical resistivity value (ERV, ρ) was highly influenced by the variations of soil basic physical properties (BPP) with particular reference to moisture content (w), densities (ρbulk/dry), void ratio (e), porosity (η) and particle grain fraction (d) of soil. Strong relationship between ERV and BPP can be clearly presents such as ρ ∞ 1/w, ρ ∞ 1/ρbulk/dry, ρ ∞ e and ρ ∞ η. This study therefore contributes a means of ERV data interpretation using BPP in order to reduce ambiguity of ERV result and interpretation discussed among related persons such as geophysicist, engineers and geologist who applied these electrical resistivity techniques in subsurface profile assessment.

Soils as Sediment database: closing a gap between soil science and geomorphology

NASA Astrophysics Data System (ADS)

Kuhn, Nikolaus J.

2016-04-01

Soils are an interface between the Earth's spheres and shaped by the nature of the interaction between them. The relevance of soil properties for the nature of the interaction between atmosphere, hydrosphere and biosphere is well-studied and accepted, on point- or ecotone-scale. However, this understanding of the largely vertical connections between spheres is not matched by a similar recognition of soil properties affecting processes acting largely in a lateral way across the land surface, such as erosion, transport and deposition of soil. Key areas where such an understanding is essential are all issues related to the lateral movement of soil-bound substances that affect the nature of soils itself, as well as water or vegetation downslope from the source area. The redistribution of eroded soil falls several disciplines, most notably soil science, agronomy, hydrology and geomorphology. Accordingly, the way sediment is described differs: in soil science, aggregation and structure are essential properties, while most process-based soil erosion models treat soil as a mixture of individual mineral grains, based on concepts derived in fluvial geomorphology or civil engineering. The actual behavior of aggregated sediment is not reflected by either approach and difficult to capture due to the dynamic nature of aggregation, especially in an environment such as running water. Still, a proxy to assess the uncertainties introduced by aggregation on the behavior of soil as sediment would represent a step forward. To develop such a proxy, a database collating relevant soil and sediment properties could serve as an initial step to identify which soil types and erosion scenarios are prone to generate a high uncertainty compared to the use of soil texture in erosion models. Furthermore, it could serve to develop standardized analytical procedures for appropriate description of soil as sediment.

Application of Electrokinetic Stabilisation (EKS) Method for Soft Soil: A Review

NASA Astrophysics Data System (ADS)

Azhar, ATS; Azim, MAM; Syakeera, NN; Jefferson, IF; Rogers, CDF

2017-08-01

Soil properties such as low shear strength, excessive compression, collapsing behavior, high swell potential are some of the undesirable properties of soils in geotechnical engineering and those properties would cause severe distress to the structures. To solve these, an innovative stabilization of Electrokinetic (EKS) has been introduced. Electrokinetic is an applicable technique to transport charged particles and fluid in an electric potential. The EKS demonstrates changes in soil pH due to electrolysis reactions, water flow between the electrodes and migration of ions towards the cathode. This treatment has proven its efficiency in consolidating organic, peat and clayey silt as well as less expensive than other methods. Otherwise, this method also gives advantage by not disturbing site. The primary objective of this review is to discuss the application of electrokinetic and to investigate the current knowledge of electrokinetic in geotechnical application through a literature search and review, including consideration of certain aspects related to the soft soil application that may be relevant to the future study and at the same time addressing some key issues and their implications on soil behaviors.

Research on the Properties of the Waste Glass Concrete Composite Foundation

NASA Astrophysics Data System (ADS)

Jia, Shilong; Chen, Kaihui; Chen, Zhongliang

2018-02-01

The composite foundation of glass concrete can not only reuse the large number of waste glass, but also improve the bearing capacity of weak foundation and soil with special properties. In this paper, the engineering properties of glass concrete composite foundation are studied based on the development situation of glass concrete and the technology of composite foundation.

Seismology in civil engineering

NASA Astrophysics Data System (ADS)

Dvorak, A.

Properties of soils and rocks exposed to vibrations in the practice of civil engineering are examined. Seismic and dynamic field investigations, determination of seismic and dynamic modulus of elasticity, coefficients of damping and absorption are studied. Seismic effects of blasting and of other sources of vibrations on structures and persons, application of rock-noise and dynamic tests of piles are studied.

Research progress on expansive soil cracks under changing environment.

PubMed

Shi, Bei-xiao; Zheng, Cheng-feng; Wu, Jin-kun

2014-01-01

Engineering problems shunned previously rise to the surface gradually with the activities of reforming the natural world in depth, the problem of expansive soil crack under the changing environment becoming a control factor of expansive soil slope stability. The problem of expansive soil crack has gradually become a research hotspot, elaborates the occurrence and development of cracks from the basic properties of expansive soil, and points out the role of controlling the crack of expansive soil strength. We summarize the existing research methods and results of expansive soil crack characteristics. Improving crack measurement and calculation method and researching the crack depth measurement, statistical analysis method, crack depth and surface feature relationship will be the future direction.

Laboratory study on subgrade soil stabilization using RBI grade 81

NASA Astrophysics Data System (ADS)

Cynthia, J. Bernadette; Kamalambikai, B.; Prasanna Kumar, R.; Dharini, K.

2017-07-01

The present study investigates the effect of reinforcing the sub grade soils with RBI 81 material. A soil nearby was collected and preliminary tests were conducted to classify the soil and it was found from the results that the sample collected was a poorly graded clay. Subsequently Tests such as Proctor Compaction, CBR, and UCC were conducted to study the various engineering properties of the identified soil. In addition to the above tests were also conducted on the soil by reinforcing with varying percentages of RBI 81. From the analysis of test results it was found that this material (RBI 81) will significantly improve the CBR value of the soil.

Accuracy of three-dimensional seismic ground response analysis in time domain using nonlinear numerical simulations

NASA Astrophysics Data System (ADS)

Liang, Fayun; Chen, Haibing; Huang, Maosong

2017-07-01

To provide appropriate uses of nonlinear ground response analysis for engineering practice, a three-dimensional soil column with a distributed mass system and a time domain numerical analysis were implemented on the OpenSees simulation platform. The standard mesh of a three-dimensional soil column was suggested to be satisfied with the specified maximum frequency. The layered soil column was divided into multiple sub-soils with a different viscous damping matrix according to the shear velocities as the soil properties were significantly different. It was necessary to use a combination of other one-dimensional or three-dimensional nonlinear seismic ground analysis programs to confirm the applicability of nonlinear seismic ground motion response analysis procedures in soft soil or for strong earthquakes. The accuracy of the three-dimensional soil column finite element method was verified by dynamic centrifuge model testing under different peak accelerations of the earthquake. As a result, nonlinear seismic ground motion response analysis procedures were improved in this study. The accuracy and efficiency of the three-dimensional seismic ground response analysis can be adapted to the requirements of engineering practice.

Pit bearing capacity effect on status of soil plug during pile driving in ocean engineering

NASA Astrophysics Data System (ADS)

Yan, Shu-Wang; Zhou, Qun-Hua; Liu, Run; Dong, Wei

2011-06-01

Foundation piles of the offshore oil platforms in the Bohai Bay are usually longer than 100 m with a diameter larger than 2 m. Driving such long and large-sized piles into the ground is a difficult task. It needs a comprehensive consider ation of the pile dimensions, soil properties and the hammer energy. Thoughtful drivability analysis has to be performed in the design stage. It has been shown that judging whether the soil column inside the pile is fully plugged, which makes the pile behave as close-ended, strongly influences the accuracy of drivability analysis. Engineering practice repeatedly indicates that the current methods widely used for soil plug judgment often give incorrect results, leading the designers to make a wrong decision. It has been found that this problem is caused by the ignorance of the bearing capacity provided by the soil surrounding the pile. Based on the Terzaghi's bearing capacity calculation method for deep foundation, a new approach for judging soil plug status is put forward, in which the surcharge effect has been considered and the dynamic effect coefficient is included. This approach has been applied to some practical engineering projects successfully, which may give more reasonable results than the currently used method does.

Amending Jasper County, Missouri soils with biochar and ...

EPA Pesticide Factsheets

Abandoned mines and the residuals from mining across the U.S. pose a considerable, pervasive risk to human health and the environment. Many soils in the Tri-State-Mining District (TSMD), located where Missouri, Kansas and Oklahoma meet, have been affected by the residuals of historic lead and zinc mining. Here we describe a research collaboration between ORD and Region 7 to investigate the use of customized soil amendments, which will include biochar, as a tool to provide both soil remediation and reestablishment of a soil-stabilizing native plant community at sites in the TSMD. Biochar is a charcoal-like, carbon-rich, porous by-product of thermal pyrolysis or gasification. A benefit of using biochar is the ability to engineer its properties to correspond to specific soil remediation needs. Specifically, it has properties that make it well suited for use in remediating mine soils and reestablishing vegetation, with studies indicating that biochar can complex and immobilize heavy metals. This is of critical importance for mining influenced sites. However, the optimized biochar properties for the remediation of acidic mine soils are not yet fully known. Biochar can be produced to have a range of pH values, depending upon feedstock and pyrolysis or gasification conditions, and post-production activation. Therefore, this material may be used as a liming agent to raise soil pH. Additionally, some biochars have been shown to improve soil water holding capacities and

Effect of Cold Temperature on the Dielectric Constant of Soil

DTIC Science & Technology

2012-04-01

explosive device (IED) threats is ground-penetrating radar ( GPR ). Proper development of GPR technology for this application requires a unique...success or failure of GPR as a detection technique. One soil property of interest to radar engineers is the dielectric constant. Previous...results to temperatures, moisture levels, and frequencies relevant to GPR systems. 2. Dielectric Constant and the Ring-resonator Concept The two

Surfactant-Induced Changes of Water Flow and Solute Transport in Soils

NASA Astrophysics Data System (ADS)

Kinsey, E. N.; Korte, C.; Peng, Z.; Yu, C.; Powelson, D.; Jacobson, A. R.; Baveye, P. C.; Darnault, C. J. G.

2016-12-01

Surfactants are present in the environment due to agricultural practices such as irrigation with wastewater, biosolid soil amendments, and/or environmental engineering remediation. Furthermore, surfactants occur widely in soils due to the application of pesticides in surfactant solution sprays, or the application of surfactants as soil wetting agents. Surfactants, because they are amphiphilic and impact the surface tension of aqueous solutions and the contact angle between aqueous and solid phases have the potential to influence water flow in porous media and the physicochemical properties of soils. The objective of this study was to assess the impact of surfactant on the soil infiltration process. Four different soils were used in this study: two sandy loam soils (Lewiston and Greenson series) and two loamy sand soils (Sparta and Gilford series). Rainfall was simulated to flow through different columns filled with the four different types of soil and effluent samples were collected at the end of each column. Each type of soil had two columns, one with a non-ionic surfactant Aerosol®22 at twice the critical micelle concentration, in the rainfall solution and one without. A conservative tracer, potassium bromide, was added to all rainfalls to monitor the infiltration process in soil. Tracer breakthrough curves were used to characterize flow in soils. Flow rates were also recorded for each soil. The presence of surfactant decreased the flow rate by a significant amount in most soil types. The decrease in flow rate can be attributed to the effects on the soil properties of hydraulic conductivity and soil aggregates. A decrease in pore space from the swelling of the soil particles can decrease the hydraulic conductivity. The properties in surfactants also decrease the surface tension and therefore soil particles are able to be dislodged from soil aggregates and cause potential soil clogging.

Engineering Properties of Clay Shales. Report 5. Strength and Deformation Properties of Pepper and Del Rio Clay Shales from Waco Dam.

DTIC Science & Technology

1984-04-01

DOwe Entered) Unclassified SECURITY CLASSIFICATION OF THIS PAGIMCe. Deja Na006 20. ABSTRACT (Continued). "standard soil testing techniques on the...0 *a .J - to >C 4*4 .4 W ( 0 0 .4) .4 aoCC 0n- y 0 5w 4 C7%C 00 ’A 0V fa vU eq I CORPS OF ENGINEERS 0/ .0 0 A 󈧄,0 0ioto 50200 A 25;C A 3O,00 A ON

Sustainable Development and Energy Geotechnology Potential Roles for Geotechnical Engineering

DOE Office of Scientific and Technical Information (OSTI.GOV)

FragaszyProgram Dire, Dr. R. J.; Santamarina, Carlos; Espinoza, N.

2011-01-01

The world is facing unprecedented challenges related to energy resources, global climate change, material use, and waste generation. Failure to address these challenges will inhibit the growth of the developing world and will negatively impact the standard of living and security of future generations in all nations. The solutions to these challenges will require multidisciplinary research across the social and physical sciences and engineering. Although perhaps not always recognized, geotechnical engineering expertise is critical to the solution of many energy and sustainability-related problems. Hence, geotechnical engineers and academicians have opportunity and responsibility to contribute to the solution of these worldwidemore » problems. Research will need to be extended to non-standard issues such as thermal properties of soils; sediment and rock response to extreme conditions and at very long time scales; coupled hydro-chemo-thermo-bio-mechanical processes; positive feedback systems; the development of discontinuities; biological modification of soil properties; spatial variability; and emergent phenomena. Clearly, the challenges facing geotechnical engineering in the future will require a much broader knowledge base than our traditional educational programs provide. The geotechnical engineering curricula, from undergraduate education through continuing professional education, must address the changing needs of a profession that will increasingly be engaged in alternative/renewable energy production; energy efficiency; sustainable design, enhanced and more efficient use of natural resources, waste management, and underground utilization.« less

76 FR 48070 - Regulated Navigation Area, Zidell Waterfront Property, Willamette River, OR

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-08

... Regulated Navigation Area (RNA) at the Zidell Waterfront Property located on the Willamette River in Portland, Oregon. This RNA is necessary to preserve the integrity of an engineered sediment cap as part of... shoreline soil in these areas. As such, this RNA is necessary to help ensure the cap is protected and will...

Structural changes of green roof growing substrate layer studied by X-ray CT

NASA Astrophysics Data System (ADS)

Jelinkova, Vladimira; Sacha, Jan; Dohnal, Michal; Snehota, Michal

2017-04-01

Increasing interest in green infrastructure linked with newly implemented legislation/rules/laws worldwide opens up research potential for field of soil hydrology. A better understanding of function of engineered soils involved in green infrastructure solutions such as green roofs or rain garden is needed. A soil layer is considered as a highly significant component of the aforesaid systems. In comparison with a natural soil, the engineered soil is assumed to be the more challenging case due to rapid structure changes early stages after its build-up. The green infrastructure efficiency depends on the physical and chemical properties of the soil, which are, in the case of engineered soils, a function of its initial composition and subsequent soil formation processes. The project presented in this paper is focused on fundamental processes in the relatively thick layer of engineered soil. The initial structure development, during which the pore geometry is altered by the growth of plant roots, water influx, solid particles translocation and other soil formation processes, is investigated with the help of noninvasive imaging technique  X-ray computed tomography. The soil development has been studied on undisturbed soil samples taken periodically from green roof test system during early stages of its life cycle. Two approaches and sample sizes were employed. In the first approach, undisturbed samples (volume of about 63 cm3) were taken each time from the test site and scanned by X-ray CT. In the second approach, samples (volume of about 630 cm3) were permanently installed at the test site and has been repeatedly removed to perform X-ray CT imaging. CT-derived macroporosity profiles reveal significant temporal changes of soil structure. Clogging of pores by fine particles and fissures development are two most significant changes that would affect the green roof system efficiency. This work has been supported by the Ministry of Education, Youth and Sports within National Sustainability Programme I, project number LO1605 and with financial support from the Czech Science Foundation under project number GAČR 17-21011S.

California Bearing Ratio (CBR) test on stabilization of clay with lime addition

NASA Astrophysics Data System (ADS)

Hastuty, I. P.; Roesyanto; Limbong, M. N.; Oberlyn, S. J.

2018-02-01

Clay is a type of soil with particles of certain minerals giving plastic properties when mixed with water. Soil has an important role in a construction, besides as a building material in a wide variety of civil engineering works, soil is also used as supporting foundation of the building. Basic properties of clay are rock-solid in dry and plastic with medium water content. In high water content, clay becomes sticky like (cohesive) and soften. Therefore, clay stabilization is necessary to repair soil’s mechanical properties. In this research, lime is use as a stabilizer that contains the Ca+ element to bond bigger particles. Lime used is slaked lime Ca(OH)2. Clay used has liquid limitation (LL) value of 47.33%, plasticity index of 29.88% and CBR value 6.29. The results explain about 10% lime mixture variation gives the optimum stabilized clay with CBR value of 8.75%.

Application of Time Domain Reflectometers in Urban Settings ...

EPA Pesticide Factsheets

Time domain reflectometers (TDRs) are sensors that measure the volumetric water content of soils and porous media. The sensors consist of stainless steel rods connected to a circuit board in an epoxy housing. An electromagnetic pulse is propagated along the rods. The time, or period, required for the signal to travel down the rods and back varies with the volumetric water content of the surrounding media and temperature. A calibration curve is needed for the specific media. TDRs were developed mostly for agricultural applications; however, the technology has also been applied to forestry and ecological research. This study demonstrates the use of TDRs for quantifying drainage properties in low impact development (LID) stormwater controls, specifically permeable pavement and rain garden systems. TDRs were successfully used to monitor the responses of urban fill, engineered bioretention media, and the aggregate storage layer under permeable pavement to multiple rain events of varying depth, intensity, and duration. The hydrologic performance of permeable pavement and rain garden systems has previously been quantified for underdrain systems, but there have been few studies of systems that drain to the underlying soils. We know of no published studies outlining the use of TDR technology to document drainage properties in media other than soil. In this study TDRs were installed at multiple locations and depths in underlying urban fill soils, engineered bior

Improving design phase evaluations for high pile rebound sites : final report.

DOT National Transportation Integrated Search

2016-05-31

A testing program performed to help determine typical soils properties encountered during pile installation when high rebound : occurs produced a decision matrix for geotechnical engineers. High pile rebound (HPR) occurred at numerous sites in Florid...

Evolutionary-based approaches for determining the deviatoric stress of calcareous sands

NASA Astrophysics Data System (ADS)

Shahnazari, Habib; Tutunchian, Mohammad A.; Rezvani, Reza; Valizadeh, Fatemeh

2013-01-01

Many hydrocarbon reservoirs are located near oceans which are covered by calcareous deposits. These sediments consist mainly of the remains of marine plants or animals, so calcareous soils can have a wide variety of engineering properties. Due to their local expansion and considerable differences from terrigenous soils, the evaluation of engineering behaviors of calcareous sediments has been a major concern for geotechnical engineers in recent years. Deviatoric stress is one of the most important parameters directly affecting important shearing characteristics of soils. In this study, a dataset of experimental triaxial tests was gathered from two sources. First, the data of previous experimental studies from the literature were gathered. Then, a series of triaxial tests was performed on calcareous sands of the Persian Gulf to develop the dataset. This work resulted in a large database of experimental results on the maximum deviatoric stress of different calcareous sands. To demonstrate the capabilities of evolutionary-based approaches in modeling the deviatoric stress of calcareous sands, two promising variants of genetic programming (GP), multigene genetic programming (MGP) and gene expression programming (GEP), were applied to propose new predictive models. The models' input parameters were the physical and in-situ condition properties of soil and the output was the maximum deviatoric stress (i.e., the axial-deviator stress). The results of statistical analyses indicated the robustness of these models, and a parametric study was also conducted for further verification of the models, in which the resulting trends were consistent with the results of the experimental study. Finally, the proposed models were further simplified by applying a practical geotechnical correlation.

Laboratory Evaluation of the Effects of 3-Chloride Compounds on the Geotechnical Properties of an Expansive Subgrade Soil

NASA Astrophysics Data System (ADS)

Radhakrishnan, G.; Anjan Kumar, M.; Raju, G. V. R. Prasada

2017-12-01

Expansive soils are known to be problematic due to their nature and behavior. These soils show volume changes due to changes in moisture content, which cause distortions to structures constructed on them. Relentless efforts are being made all over the world to find solution to the problems of expansive soils. In the case of flexible pavements, unless the subgrade is appropriately treated during the construction stage, the maintenance cost will increase substantially due to deterioration. There are many methods of stabilising expansive subgrade soils. Chemical stabilisation is one such technique employed in improving the engineering properties of the expansive soil. Investigations on chemical stabilization of expansive soils revealed that conventionally used lime could be replaced by the chloride compound chemicals because of their ready dissolvability in water, ease of mixing with soil and supply of sufficient cations for ready cation exchange. The main objective of this work is to study the effectiveness of three chloride compound chemicals, ammonium chloride (NH4Cl), magnesium chloride (MgCl2) and aluminum chloride (AlCl3) on the geotechnical properties of an expansive soil. The chemicals content up to 2% were added to the soil and its effect on the index limits, swell pressure, compaction characteristics as well as California bearing ratio are studied. It was observed that aluminum chloride chemical content has a significantly higher influence than the other two chemicals and it could be recognized as an effective chemical stabilizer.

A Methodology for Soil Moisture Retrieval from Land Surface Temperature, Vegetation Index, Topography and Soil Type

NASA Astrophysics Data System (ADS)

Pradhan, N. R.

2015-12-01

Soil moisture conditions have an impact upon hydrological processes, biological and biogeochemical processes, eco-hydrology, floods and droughts due to changing climate, near-surface atmospheric conditions and the partition of incoming solar and long-wave radiation between sensible and latent heat fluxes. Hence, soil moisture conditions virtually effect on all aspects of engineering / military engineering activities such as operational mobility, detection of landmines and unexploded ordinance, natural material penetration/excavation, peaking factor analysis in dam design etc. Like other natural systems, soil moisture pattern can vary from completely disorganized (disordered, random) to highly organized. To understand this varying soil moisture pattern, this research utilized topographic wetness index from digital elevation models (DEM) along with vegetation index from remotely sensed measurements in red and near-infrared bands, as well as land surface temperature (LST) in the thermal infrared bands. This research developed a methodology to relate a combined index from DEM, LST and vegetation index with the physical soil moisture properties of soil types and the degree of saturation. The advantage in using this relationship is twofold: first it retrieves soil moisture content at the scale of soil data resolution even though the derived indexes are in a coarse resolution, and secondly the derived soil moisture distribution represents both organized and disorganized patterns of actual soil moisture. The derived soil moisture is used in driving the hydrological model simulations of runoff, sediment and nutrients.

Effect of Young's Modulus and Surface Roughness on the Inter-Particle Friction of Granular Materials.

PubMed

Sandeep, Chitta Sai; Senetakis, Kostas

2018-01-31

In the study we experimentally examine the influence of elastic properties and surface morphology on the inter-particle friction of natural soil grains. The experiments are conducted with a custom-built micromechanical apparatus and the database is enhanced by testing engineered-reference grains. Naturally-occurring geological materials are characterized by a wide spectrum of mechanical properties (e.g., Young's modulus) and surface morphology (e.g., roughness), whereas engineered grains have much more consistent characteristics. Comparing to engineered materials, geological materials are found to display more pronounced initial plastic behavior during compression. Under the low normal load range applied in the study, between 1 and 5 N, we found that the frictional force is linearly correlated with the applied normal load, but we acknowledge that the data are found more scattered for natural soil grains, especially for rough and weathered materials which have inconsistent characteristics. The inter-particle coefficient of friction is found to be inversely correlated with the Young's modulus and the surface roughness. These findings are important in geophysical and petroleum engineering contents, since a number of applications, such as landslides and granular flows, hydraulic fracturing using proppants, and weathering process of cliffs, among others, can be simulated using discrete numerical methods. These methods employ contact mechanics properties at the grain scale and the inter-particle friction is one of these critical components. It is stressed in our study that friction is well correlated with the elastic and morphological characteristics of the grains.

Nondestructive evaluation of warm mix asphalt through resonant column testing.

DOT National Transportation Integrated Search

2014-02-01

Non-destructive testing has been used for decades to characterize engineering properties of hot-mix asphalt. Among such tests is the resonant column (RC) test, which is commonly used to characterize soil materials. The resonant column device at Penn ...

Engineered polymeric nanoparticles for soil remediation.

PubMed

Tungittiplakorn, Warapong; Lion, Leonard W; Cohen, Claude; Kim, Ju-Young

2004-03-01

Hydrophobic organic groundwater contaminants, such as polynuclear aromatic hydrocarbons (PAHs), sorb strongly to soils and are difficult to remove. We report here on the synthesis of amphiphilic polyurethane (APU) nanoparticles for use in remediation of soil contaminated with PAHs. The particles are made of polyurethane acrylate anionomer (UAA) or poly(ethylene glycol)-modified urethane acrylate (PMUA) precursor chains that can be emulsified and cross-linked in water. The resulting particles are of colloidal size (17-97 nm as measured by dynamic light scattering). APU particles have the ability to enhance PAH desorption and transport in a manner comparable to that of surfactant micelles, but unlike the surface-active components of micelles, the individual cross-linked precursor chains in APU particles are not free to sorb to the soil surface. Thus, the APU particles are stable independent of their concentration in the aqueous phase. In this paper we show that APU particles can be engineered to achieve desired properties. Our experimental results show that the APU particles can be designed to have hydrophobic interior regions that confer a high affinity for phenanthrene (PHEN) and hydrophilic surfaces that promote particle mobility in soil. The affinity of APU particles for contaminants such as PHEN can be controlled by changing the size of the hydrophobic segment used in the chain synthesis. The mobility of colloidal APU suspensions in soil is controlled by the charge density or the size of the pendent water-soluble chains that reside on the particle surface. Exemplary results are provided illustrating the influence of alternative APU particle formulations with respect to their efficacy for contaminant removal. The ability to control particle properties offers the potential to produce different nanoparticles optimized for varying contaminant types and soil conditions.

The Evolution and Development of the Lunar Regolith and Implications for Lunar Surface Operations and Construction

NASA Technical Reports Server (NTRS)

McKay, David

2009-01-01

The lunar regolith consists of about 90% submillimeter particles traditionally termed lunar soil. The remainder consists of larger particles ranging up to boulder size rocks. At the lower size end, soil particles in the 10s of nanometer sizes are present in all soil samples. Lunar regolith overlies bedrock which consists of either lava flows in mare regions or impact-produced megaregolith in highland regions. Lunar regolith has been produced over billions of years by a combination of breaking and communition of bedrock by meteorite bombardment coupled with a variety of complex space weathering processes including solar wind implantation, solar flare and cosmic ray bombardment with attendant radiation damage, melting, vaporization, and vapor condensation driven by impact, and gardening and turnover of the resultant soil. Lunar regolith is poorly sorted compared to most terrestrial soils, and has interesting engineering properties including strong grain adhesion, over-compacted soil density, an abundance of agglutinates with sharp corners, and a variety of properties related to soil maturity. The NASA program has supported a variety of engineering test research projects, the production of bricks by solar or microwave sintering, the production of concrete, the in situ sintering and glazing of regolith by microwave, and the extraction of useful resources such as oxygen, hydrogen, iron, aluminum, silicon and other products. Future requirements for a lunar surface base or outpost will include construction of protective berms, construction of paved roadways, construction of shelters, movement and emplacement of regolith for radiation shielding and thermal control, and extraction of useful products. One early need is for light weight but powerful digging, trenching, and regolith-moving equipment.

Effects of fines content on hydraulic conductivity and morphology of laterite soil as hydraulic barrier

NASA Astrophysics Data System (ADS)

Bello Yamusa, Yamusa; Yunus, Nor Zurairahetty Mohd; Ahmad, Kamarudin; Rahman, Norhan Abd; Sa'ari, Radzuan

2018-03-01

Laterite soil was investigated to find out the effects of fines content and to identify the micro-structural and molecular characteristics to evaluate its potentiality as a compacted soil landfill liner material. Tests were carried out on natural soil and reconstituted soil by dry weight of soil samples to determine the physical and engineering properties of the soil. All tests were carried out on the samples by adopting the British Standard 1377:1990. The possible mechanisms that contributed to the clay mineralogy were analyzed using spectroscopic and microscopic techniques such as field emission scanning electron microscopy (FESEM), energy-dispersive X-ray (EDX) and X-ray diffractometry (XRD). The laterite soil was found to contain kaolinite as the major clay minerals. A minimum of 50% fines content of laterite soil met the required result for hydraulic barriers in waste containment facilities.

Update of correlations between cone penetration and boring log data.

DOT National Transportation Integrated Search

2008-03-01

The cone penetration test (CPT) has been widely used in Louisiana in the last two decades as an in situ tool to characterize engineering : properties of soils. In addition, conventional drilling and sample retrieval using Shelby tube followed by labo...

La-oxides as tracers for PuO{sub 2} to simulate contaminated aerosol behavior

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meyer, L.C.; Newton, G.J.; Cronenberg, A.W.

1994-04-01

An analytical and experimental study was performed on the use of lanthanide oxides (La-oxides) as surrogates for plutonium oxides (PuO{sub 2}) during simulated buried waste retrieval. This study determined how well the La-oxides move compared to PuO{sub 2} in aerosolized soils during retrieval scenarios. As part of the analytical study, physical properties of La-oxides and PuO{sub 2}, such as molecular diameter, diffusivity, density, and molecular weight are compared. In addition, an experimental study was performed in which Idaho National Engineering Laboratory (INEL) soil, INEL soil with lanthanides, and INEL soil with plutonium were aerosolized and collected in filters. Comparison ofmore » particle size distribution parameters from this experimental study show similarity between INEL soil, INEL soil with lanthanides, and INEL soil with plutonium.« less

Ground penetrating radar for underground sensing in agriculture: a review

NASA Astrophysics Data System (ADS)

Liu, Xiuwei; Dong, Xuejun; Leskovar, Daniel I.

2016-10-01

Belowground properties strongly affect agricultural productivity. Traditional methods for quantifying belowground properties are destructive, labor-intensive and pointbased. Ground penetrating radar can provide non-invasive, areal, and repeatable underground measurements. This article reviews the application of ground penetrating radar for soil and root measurements and discusses potential approaches to overcome challenges facing ground penetrating radar-based sensing in agriculture, especially for soil physical characteristics and crop root measurements. Though advanced data-analysis has been developed for ground penetrating radar-based sensing of soil moisture and soil clay content in civil engineering and geosciences, it has not been used widely in agricultural research. Also, past studies using ground penetrating radar in root research have been focused mainly on coarse root measurement. Currently, it is difficult to measure individual crop roots directly using ground penetrating radar, but it is possible to sense root cohorts within a soil volume grid as a functional constituent modifying bulk soil dielectric permittivity. Alternatively, ground penetrating radarbased sensing of soil water content, soil nutrition and texture can be utilized to inversely estimate root development by coupling soil water flow modeling with the seasonality of plant root growth patterns. Further benefits of ground penetrating radar applications in agriculture rely on the knowledge, discovery, and integration among differing disciplines adapted to research in agricultural management.

Correlation of the Rock Mass Rating (RMR) System with the Unified Soil Classification System (USCS): Introduction of the Weak Rock Mass Rating System (W-RMR)

NASA Astrophysics Data System (ADS)

Warren, Sean N.; Kallu, Raj R.; Barnard, Chase K.

2016-11-01

Underground gold mines in Nevada are exploiting increasingly deeper ore bodies comprised of weak to very weak rock masses. The Rock Mass Rating (RMR) classification system is widely used at underground gold mines in Nevada and is applicable in fair to good-quality rock masses, but is difficult to apply and loses reliability in very weak rock mass to soil-like material. Because very weak rock masses are transition materials that border engineering rock mass and soil classification systems, soil classification may sometimes be easier and more appropriate to provide insight into material behavior and properties. The Unified Soil Classification System (USCS) is the most likely choice for the classification of very weak rock mass to soil-like material because of its accepted use in tunnel engineering projects and its ability to predict soil-like material behavior underground. A correlation between the RMR and USCS systems was developed by comparing underground geotechnical RMR mapping to laboratory testing of bulk samples from the same locations, thereby assigning a numeric RMR value to the USCS classification that can be used in spreadsheet calculations and geostatistical analyses. The geotechnical classification system presented in this paper including a USCS-RMR correlation, RMR rating equations, and the Geo-Pick Strike Index is collectively introduced as the Weak Rock Mass Rating System (W-RMR). It is the authors' hope that this system will aid in the classification of weak rock masses and more usable design tools based on the RMR system. More broadly, the RMR-USCS correlation and the W-RMR system help define the transition between engineering soil and rock mass classification systems and may provide insight for geotechnical design in very weak rock masses.

Thermal Conductivity in Soil: Theoretical Approach by 3D Infinite Resistance Grid Model

NASA Astrophysics Data System (ADS)

Changjan, A.; Intaravicha, N.

2018-05-01

Thermal conductivity in soil was elementary characteristic of soil that conduct heat, measured in terms of Fourier’s Law for heat conduction and useful application in many fields: such as Utilizing underground cable for transmission and distribution systems, the rate of cooling of the cable depends on the thermal properties of the soil surrounding the cable. In this paper, we investigated thermal conductivity in soil by infinite three dimensions (3D) electrical resistance circuit concept. Infinite resistance grid 3D was the grid of resistors that extends to infinity in all directions. Model of thermal conductivity in soil of this research was generated from this concept: comparison between electrical resistance and thermal resistance in soil. Finally, we investigated the analytical form of thermal conductivity in soil which helpful for engineering and science students that could exhibit education with a principle of physics that applied to real situations.

Land-use and land-management change: relationships with earthworm and fungi communities and soil structural properties.

PubMed

Spurgeon, David J; Keith, Aidan M; Schmidt, Olaf; Lammertsma, Dennis R; Faber, Jack H

2013-12-01

Change in land use and management can impact massively on soil ecosystems. Ecosystem engineers and other functional biodiversity in soils can be influenced directly by such change and this in turn can affect key soil functions. Here, we employ meta-analysis to provide a quantitative assessment of the effects of changes in land use and land management across a range of successional/extensification transitions (conventional arable → no or reduced tillage → grassland → wooded land) on community metrics for two functionally important soil taxa, earthworms and fungi. An analysis of the relationships between community change and soil structural properties was also included. Meta-analysis highlighted a consistent trend of increased earthworm and fungal community abundances and complexity following transitions to lower intensity and later successional land uses. The greatest changes were seen for early stage transitions, such as introduction of reduced tillage regimes and conversion to grassland from arable land. Not all changes, however, result in positive effects on the assessed community metrics. For example, whether woodland conversion positively or negatively affects community size and complexity depends on woodland type and, potentially, the changes in soil properties, such as pH, that may occur during conversion. Alterations in soil communities tended to facilitate subsequent changes in soil structure and hydrology. For example, increasing earthworm abundances and functional group composition were shown to be positively correlated with water infiltration rate (dependent on tillage regime and habitat characteristics); while positive changes in fungal biomass measures were positively associated with soil microaggregate stability. These findings raise the potential to manage landscapes to increase ecosystem service provision from soil biota in relation to regulation of soil structure and water flow.

Basic Aspects of Deep Soil Mixing Technology Control

NASA Astrophysics Data System (ADS)

Egorova, Alexandra A.; Rybak, Jarosław; Stefaniuk, Damian; Zajączkowski, Przemysław

2017-10-01

Improving a soil is a process of increasing its physical/mechanical properties without changing its natural structure. Improvement of soil subbase is reached by means of the knitted materials, or other methods when strong connection between soil particles is established. The method of DSM (Deep Soil Mixing) columns has been invented in Japan in 1970s. The main reason of designing cement-soil columns is to improve properties of local soils (such as strength and stiffness) by mixing them with various cementing materials. Cement and calcium are the most commonly used binders. However new research undertaken worldwide proves that apart from these materials, also gypsum or fly ashes can also be successfully implemented. As the Deep Soil Mixing is still being under development, anticipating mechanical properties of columns in particular soils and the usage of cementing materials in formed columns is very difficult and often inappropriate to predict. That is why a research is carried out in order to find out what binders and mixing technology should be used. The paper presents several remarks on the testing procedures related to quality and capacity control of Deep Soil Mixing columns. Soil improvement methods, their advantages and limitations are briefly described. The authors analyse the suitability of selected testing methods on subsequent stages of design and execution of special foundations works. Chosen examples from engineering practice form the basis for recommendations for the control procedures. Presented case studies concerning testing the on capacity field samples and laboratory procedures on various categories of soil-cement samples were picked from R&D and consulting works offered by Wroclaw University of Science and Technology. Special emphasis is paid to climate conditions which may affect the availability of performing and controlling of DSM techniques in polar zones, with a special regard to sample curing.

Lunar surface engineering properties experiment definition. Volume 2: Mechanics of rolling sphere-soil slope interaction

NASA Technical Reports Server (NTRS)

Hovland, H. J.; Mitchell, J. K.

1971-01-01

The soil deformation mode under the action of a rolling sphere (boulder) was determined, and a theory based on actual soil failure mechanism was developed which provides a remote reconnaissance technique for study of soil conditions using boulder track observations. The failure mechanism was investigated by using models and by testing an instrumented spherical wheel. The wheel was specifically designed to measure contact pressure, but it also provided information on the failure mechanism. Further tests included rolling some 200 spheres down sand slopes. Films were taken of the rolling spheres, and the tracks were measured. Implications of the results and reevaluation of the lunar boulder tracks are discussed.

In-tank precipitation facility (ITP) and H-Tank Farm (HTF) geotechnical report, WSRC-TR-95-0057, Revision 0, Volume 5

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

A geotechnical study has been completed in H-Area for the In-Tank Precipitation Facility (ITP) and the balance of the H-Area Tank Farm (HTF) at the Savannah River Site (SRS) in South Carolina. The study consisted of subsurface field exploration, field and laboratory testing, and engineering analyses. The purpose of these investigations is to evaluate the overall stability of the H-Area tanks under static and dynamic conditions. The objectives of the study are to define the site-specific geological conditions at ITP and HTF, obtain engineering properties for the assessment of the stability of the native soils and embankment under static andmore » dynamic loads (i.e., slope stability, liquefaction potential, and potential settlements), and derive properties for soil-structure interaction studies. This document (Volume 5) contains the laboratory test results for the In-Tank Precipitation Facility (ITP) and H-Tank Farm (HTF) Geotechnical Report.« less

Evaluation of engineering properties for the use of leached brown coal ash in soil covers.

PubMed

Mudd, Gavin M; Chakrabarti, Srijib; Kodikara, Jayantha

2007-01-31

The need to engineer cover systems for the successful rehabilitation or remediation of a wide variety of solid wastes is increasing. Some common applications include landfills, hazardous waste repositories, or mine tailings dams and waste rock/overburden dumps. The brown coal industry of the Latrobe Valley region of Victoria, Australia, produces significant quantities of coal ash and overburden annually. There are some site-specific acid mine drainage (AMD) issues associated with overburden material. This needs to be addressed both during the operational phase of a project and during rehabilitation. An innovative approach was taken to investigate the potential to use leached brown coal ash in engineered soil covers on this overburden dump. The basis for this is two-fold: first, the ash has favourable physical characteristics for use in cover systems (such as high storage capacity/porosity, moderately low permeability, and an ability to act as a capillary break layer generating minimal leachate or seepage); and second, the leachate from the ash is mildly alkaline (which can help to mitigate and reduce the risk of AMD). This paper will review the engineering issues involved in using leached brown coal ash in designing soil covers for potentially acid-forming overburden dumps. It presents the results of laboratory work investigating the technical feasibility of using leached brown coal ash in engineered solid waste cover systems.

Engineering Biochar Hydrophobicity to Mitigate Risk of Top-Soil Erosion

NASA Astrophysics Data System (ADS)

Kinney, T. J.; Dean, M. R.; Hockaday, W. C.; Masiello, C. A.

2009-12-01

The pyrolysis of biomass is a net carbon negative method of sequestering atmospheric carbon as recalcitrant black carbon. The resulting solid product, called biochar, is likely to improve agricultural soils when used as a soil conditioner in sustainable land management practice. Biochar has been shown to improve crop yields, improve water-holding capacity in sandy soils, increase cation exchange capacity (CEC), and retain nutrients from fertilization longer than soils unamended with biochar. Biochar undoubtedly has high potential as both a carbon management tool and a tool to increase global food production. However, little is understood about possible side effects of biochar in agricultural soils such as ecosystem toxicity, interactions with biota, and modification of soil hydrologic properties, such as permeability. The hydrophobicity of a soil determines how easily precipitation can permeate soil pores. Water that fails to permeate is redirected as runoff, responsible for the detachment and transport of nutrient-rich topsoil particles. Mitigating top-soil erosion is an important aspect of sustainable land management. Biochar, primarily composed of condensed aromatic structures, is a hydrophobic material and incorporating it into agricultural soils may act to alter soil hydrology through multiple avenues. These include a likely increase in soil water-holding capacity (a positive outcome) and a potential increase in soil hydrophobicity (a negative outcome). In an effort to understand how to engineer reduced biochar hydrophobicity, we investigated the hydrophobicity of biochars as a function of biomass feedstock, pyrolysis temperatures, and post-pyrolysis chemical treatments. We used Water Drop Penetration Time (WDPT) and Molarity of an Ethanol Drop (MED) tests to measure hydrophobicity, and FTIR, CPMAS-NMR, and N2-BET to probe the surface chemistry, bulk chemistry, and surface area of various biochars, respectively. We used post-pyrolysis chemical treatments of biochar to study the origin of biochar hydrophobicity and to assess the possibility of reducing hydrophobicity prior to soil amendment. We used correlative analysis to study the relationship between hydrophobicity, biomass and pyrolysis characteristics, as well as chemical treatments. Future work will focus on engineering designer biochars which minimize hydrophobicity while maximizing positive benefits, such as ion exchange capacity.

Determination of the Thermal Properties of Sands as Affected by Water Content, Drainage/Wetting, and Porosity Conditions for Sands With Different Grain Sizes

NASA Astrophysics Data System (ADS)

Smits, K. M.; Sakaki, T.; Limsuwat, A.; Illangasekare, T. H.

2009-05-01

It is widely recognized that liquid water, water vapor and temperature movement in the subsurface near the land/atmosphere interface are strongly coupled, influencing many agricultural, biological and engineering applications such as irrigation practices, the assessment of contaminant transport and the detection of buried landmines. In these systems, a clear understanding of how variations in water content, soil drainage/wetting history, porosity conditions and grain size affect the soil's thermal behavior is needed, however, the consideration of all factors is rare as very few experimental data showing the effects of these variations are available. In this study, the effect of soil moisture, drainage/wetting history, and porosity on the thermal conductivity of sandy soils with different grain sizes was investigated. For this experimental investigation, several recent sensor based technologies were compiled into a Tempe cell modified to have a network of sampling ports, continuously monitoring water saturation, capillary pressure, temperature, and soil thermal properties. The water table was established at mid elevation of the cell and then lowered slowly. The initially saturated soil sample was subjected to slow drainage, wetting, and secondary drainage cycles. After liquid water drainage ceased, evaporation was induced at the surface to remove soil moisture from the sample to obtain thermal conductivity data below the residual saturation. For the test soils studied, thermal conductivity increased with increasing moisture content, soil density and grain size while thermal conductivity values were similar for soil drying/wetting behavior. Thermal properties measured in this study were then compared with independent estimates made using empirical models from literature. These soils will be used in a proposed set of experiments in intermediate scale test tanks to obtain data to validate methods and modeling tools used for landmine detection.

Beneficial reuse of fly ashes in geotechnical engineering with physicochemical and electron microscopic methods.

DOT National Transportation Integrated Search

2013-06-01

The sedimentation behavior of fine grained soil is largely dependent on its pore fluid chemistry. Physicochemical properties of the : pore fluid, such as ionic strength and pH, could greatly influence the micro structure of kaolinite which in turn in...

An evaluation of different soil washing solutions for remediating arsenic-contaminated soils.

PubMed

Wang, Yiwen; Ma, Fujun; Zhang, Qian; Peng, Changsheng; Wu, Bin; Li, Fasheng; Gu, Qingbao

2017-04-01

Soil washing is a promising way to remediate arsenic-contaminated soils. Most research has mostly focused on seeking efficient extractants for removing arsenic, but not concerned with any changes in soil properties when using this technique. In this study, the removal of arsenic from a heavily contaminated soil employing different washing solutions including H 3 PO 4 , NaOH and dithionite in EDTA was conducted. Subsequently, the changes in soil physicochemical properties and phytotoxicity of each washing technique were evaluated. After washing with 2 M H 3 PO 4 , 2 M NaOH or 0.1 M dithionite in 0.1 M EDTA, the soil samples' arsenic content met the clean-up levels stipulated in China's environmental regulations. H 3 PO 4 washing decreased soil pH, Ca, Mg, Al, Fe, and Mn concentrations but increased TN and TP contents. NaOH washing increased soil pH but decreased soil TOC, TN and TP contents. Dithionite in EDTA washing reduced soil TOC, Ca, Mg, Al, Fe, Mn and TP contents. A drastic color change was observed when the soil sample was washed with H 3 PO 4 or 0.1 M dithionite in 0.1 M EDTA. After adjusting the soil pH to neutral, wheat planted in the soil sample washed by NaOH evidenced the best growth of all three treated soil samples. These results will help with selecting the best washing solution when remediating arsenic-contaminated soils in future engineering applications. Copyright © 2017 Elsevier Ltd. All rights reserved.

Distribution and mobility of exogenous copper as influenced by aging and components interactions in three Chinese soils.

PubMed

Shi, Hanzhi; Li, Qi; Chen, Wenli; Cai, Peng; Huang, Qiaoyun

2018-04-01

Copper contamination of soils is a global environmental problem. Soil components (organic matter, clay minerals, and microorganisms) and retention time can govern the adsorption, fixation, and distribution of copper. This study evaluated the interaction effects of soil components and aging on the distribution of exogenous copper. Three typical Chinese soils (Ultisol, Alfisol, and Histosol) were collected from Hunan, Henan, and Heilongjiang Provinces. Soils were incubated with rice straw (RS) and engineered bacteria (Pseudomonas putida X4/pIME) in the presence of exogenous copper for 12 months. Sequential extraction was employed to obtain the distribution of Cu species in soils, and the mobility factors of Cu were calculated. The relationships between soil properties and Cu fractions were analyzed with stepwise multiple linear regression. The results show that organic carbon plays a more important role in shaping the distribution of relatively mobile Cu, and iron oxides can be more critical in stabilizing Cu species in soils. Our results suggest that organic matter is the most important factor influencing copper partitioning in Ultisols, while iron oxides are more significant in Alfisols. The mobility of exogenous Cu in soils depends largely on organic carbon, amorphous Fe, and aging. The introduction of both rice straw and rice straw + engineered bacteria enhanced the stabilization of Cu in all the three soils during aging process. The introduction of bacteria could reduce copper mobility, which was indicated by the lowest mobility factors of Cu for the treatment with bacteria in Black, Red, and Cinnamon soils at the first 4, 8, and 8 months, respectively. Different measures should be taken into account regarding the content of organic matter and iron oxides depending on soil types for the risk assessment and remediation of Cu-contaminated soils.

Peat soils stabilization using Effective Microorganisms (EM)

NASA Astrophysics Data System (ADS)

Yusof, N. Z.; Samsuddin, N. S.; Hanif, M. F.; Syed Osman, S. B.

2018-04-01

Peat soil is known as geotechnical problematic soil since it is the softest soil having highly organic and moisture content which led to high compressibility, low shear strength and long-term settlement. The aim of this study was to obtain the stabilized peat soils using the Effective Microorganisms (EM). The volume of EM added and mixed with peat soils varied with 2%, 4%, 6%, 8% and 10% and then were cured for 7, 14 and 21 days. The experiment was done for uncontrolled and controlled moisture content. Prior conducting the main experiments, the physical properties such as moisture content, liquid limit, specific gravity, and plastic limit etc. were measure for raw peat samples. The Unconfined Compressive Strength (UCS) test was performed followed by regression analysis to check the effect of EM on the soil strength. Obtained results have shown that the mix design for controlled moisture contents showed the promising improvement in their compressive strength. The peat soil samples with 10% of EM shows the highest increment in UCS value and the percentage of increments are in the range of 44% to 65% after curing for 21 days. The regression analysis of the EM with the soil compressive strength showed that in controlled moisture conditions, EM significantly improved the soil stability as the value of R2 ranged between 0.97 – 0.78. The results have indicated that the addition of EM in peat soils provides significant improving in the strength of the soil as well as the other engineering properties.

Bioavailability of cerium oxide nanoparticles to Raphanus sativus L. in two soils.

PubMed

Zhang, Weilan; Musante, Craig; White, Jason C; Schwab, Paul; Wang, Qiang; Ebbs, Stephen D; Ma, Xingmao

2017-01-01

Cerium oxide nanoparticles (CeO 2 NP) are a common component of many commercial products. Due to the general concerns over the potential toxicity of engineered nanoparticles (ENPs), the phytotoxicity and in planta accumulation of CeO 2 NPs have been broadly investigated. However, most previous studies were conducted in hydroponic systems and with grain crops. For a few studies performed with soil grown plants, the impact of soil properties on the fate and transport of CeO 2 NPs was generally ignored even though numerous previous studies indicate that soil properties play a critical role in the fate and transport of environmental pollutants. The objectives of this study were to evaluate the soil fractionation and bioavailability of CeO 2 NPs to Raphanus sativus L (radish) in two soil types. Our results showed that the silty loam contained slightly higher exchangeable fraction (F1) of cerium element than did loamy sand soil, but significantly lower reducible (F2) and oxidizable (F3) fractions as CeO 2 NPs concentration increased. CeO 2 NPs associated with silicate minerals or the residue fraction (F4) dominated in both soils. The cerium concentration in radish storage root showed linear correlation with the sum of the first three fractions (r 2  = 0.98 and 0.78 for loamy sand and silty loam respectively). However, the cerium content in radish shoots only exhibited strong correlations with F1 (r 2  = 0.97 and 0.89 for loamy sand and silty loam respectively). Overall, the results demonstrated that soil properties are important factors governing the distribution of CeO 2 NPs in soil and subsequent bioavailability to plants. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Physical properties of the martian surface from the viking 1 lander: preliminary results.

PubMed

Shorthill, R W; Hutton, R E; Moore, H J; Scott, R F; Spitzer, C R

1976-08-27

The purpose of the physical properties experiment is to determine the characteristics of the martian "soil" based on the use of the Viking lander imaging system, the surface sampler, and engineering sensors. Viking 1 lander made physical contact with the surface of Mars at 11:53:07.1 hours on 20 July 1976 G.M.T. Twenty-five seconds later a high-resolution image sequence of the area around a footpad was started which contained the first information about surface conditions on Mars. The next image is a survey of the martian landscape in front of the lander, including a view of the top support of two of the landing legs. Each leg has a stroke gauge which extends from the top of the leg support an amount equal to the crushing experienced by the shock absorbers during touchdown. Subsequent images provided views of all three stroke gauges which, together with the knowledge of the impact velocity, allow determination of "soil" properties. In the images there is evidence of surface erosion from the engines. Several laboratory tests were carried out prior to the mission with a descent engine to determine what surface alterations might occur during a Mars landing. On sol 2 the shroud, which protected the surface sampler collector head from biological contamination, was ejected onto the surface. Later a cylindrical pin which dropped from the boom housing of the surface sampler during the modified unlatching sequence produced a crater (the second Mars penetrometer experiment). These two experiments provided further insight into the physical properties of the martian surface.

Physical properties of the martian surface from the Viking 1 lander: preliminary results

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shorthill, R.W.; Hutton, R.E.; Moore, H.J. II

1976-08-27

The purpose of the physical properties experiment is to determine the characteristics of the martian ''soil'' based on the use of the Viking lander imaging system, the surface sampler, and engineering sensors. Viking 1 lander made physical contact with the surface of Mars at 11:53:07.1 hours on 20 July 1976 G.M.T. Twenty-five seconds later a high-resolution image sequence of the area around a footpad was started which contained the first information about surface conditions on Mars. The next image is a survey of the martian landscape in front of the lander, including a view of the top support of twomore » of the landing legs. Each leg has a stroke gauge which extends from the top of the leg support an amount equal to the crushing experienced by the shock absorbers during touchdown. Subsequent images provided views of all three stroke gauges which, together with the knowledge of the impact velocity, allow determination of ''soil'' properties. In the images there is evidence of surface erosion from the engines. Several laboratory tests were carried out prior to the mission with a descent engine to determine what surface alterations might occur during a Mars landing. On sol 2 the shroud, which protected the surface sampler collector head from biological contamination, was ejected onto the surface. Later a cylindrical pin which dropped from the boom housing of the surface sampler during the modified unlatching sequence produced a crater (the second Mars penetrometer experiment). These two experiments provided further insight into the physical properties of the martian surface.« less

Geotechnical Investigation of the Potential Use of Shredded Scrap Tires in Soil Stabilization.

DOT National Transportation Integrated Search

1998-11-01

Silt-tire and clay-tire mixtures, containing 0% to 100% shredded tire material by weight, with tire chips ranging in size from 7mm-13mm, 13mm-25mm, and 25mm-38mm, were tested for a series of engineering properties including compaction characteristics...

Engineered/designer biochar for contaminant removal/immobilization from soil and water: Potential and implication of biochar modification.

PubMed

Rajapaksha, Anushka Upamali; Chen, Season S; Tsang, Daniel C W; Zhang, Ming; Vithanage, Meththika; Mandal, Sanchita; Gao, Bin; Bolan, Nanthi S; Ok, Yong Sik

2016-04-01

The use of biochar has been suggested as a means of remediating contaminated soil and water. The practical applications of conventional biochar for contaminant immobilization and removal however need further improvements. Hence, recent attention has focused on modification of biochar with novel structures and surface properties in order to improve its remediation efficacy and environmental benefits. Engineered/designer biochars are commonly used terms to indicate application-oriented, outcome-based biochar modification or synthesis. In recent years, biochar modifications involving various methods such as, acid treatment, base treatment, amination, surfactant modification, impregnation of mineral sorbents, steam activation and magnetic modification have been widely studied. This review summarizes and evaluates biochar modification methods, corresponding mechanisms, and their benefits for contaminant management in soil and water. Applicability and performance of modification methods depend on the type of contaminants (i.e., inorganic/organic, anionic/cationic, hydrophilic/hydrophobic, polar/non-polar), environmental conditions, remediation goals, and land use purpose. In general, modification to produce engineered/designer biochar is likely to enhance the sorption capacity of biochar and its potential applications for environmental remediation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Impact of roots, mycorrhizas and earthworms on soil physical properties as assessed by shrinkage analysis

NASA Astrophysics Data System (ADS)

Milleret, R.; Le Bayon, R.-C.; Lamy, F.; Gobat, J.-M.; Boivin, P.

2009-07-01

SummarySoil biota such as earthworms, arbuscular mycorrhizal fungi (AMF) and plant roots are known to play a major role in engineering the belowground part of the terrestrial ecosystems, thus strongly influencing the water budget and quality on earth. However, the effect of soil organisms and their interactions on the numerous soil physical properties to be considered are still poorly understood. Shrinkage analysis allows quantifying a large spectrum of soil properties in a single experiment, with small standard errors. The objectives of the present study were, therefore, to assess the ability of the method to quantify changes in soil properties as induced by single or combined effects of leek roots ( Allium porrum), AMF ( Glomus intraradices) and earthworms ( Allolobophora chlorotica). The study was performed on homogenised soil microcosms and the experiments lasted 35 weeks. The volume of the root network and the external fungal hyphae was measured at the end, and undisturbed soil cores were collected. Shrinkage analysis allowed calculating the changes in soil hydro-structural stability, soil plasma and structural pore volumes, soil bulk density and plant available water, and structural pore size distributions. Data analysis revealed different impacts of the experimented soil biota on the soil physical properties. At any water content, the presence of A. chlorotica resulted in a decrease of the specific bulk volume and the hydro-structural stability around 25%, and in a significant increase in the bulk soil density. These changes went with a decrease of the structural pore volumes at any pore size, a disappearing of the thinnest structural pores, a decrease in plant available water, and a hardening of the plasma. On the contrary, leek roots decreased the bulk soil density up to 1.23 g cm -3 despite an initial bulk density of 1.15 g cm -3. This increase in volume was accompanied with a enhanced hydro-structural stability, a larger structural pore volume at any pore size, smaller structural pore radii and an increase in plant available water. Interestingly, a synergistic effect of leek roots and AMF in the absence of the earthworms was highlighted, and this synergistic effect was not observed in presence of earthworms. The structural pore volume generated by root and AMF growth was several orders of magnitude larger than the volume of the organisms. Root exudates as well as other AMF secretion have served as carbon source for bacteria that in turn would enhance soil aggregation and porosity, thus supporting the idea of a self-organization of the soil-plant-microbe complex previously described.

Crop systems and plant roots can modify the soil water holding capacity

NASA Astrophysics Data System (ADS)

Doussan, Claude; Cousin, Isabelle; Berard, Annette; Chabbi, Abad; Legendre, Laurent; Czarnes, Sonia; Toussaint, Bruce; Ruy, Stéphane

2015-04-01

At the interface between atmosphere and deep sub-soil, the root zone plays a major role in regulating the flow of water between major compartments: groundwater / surface / atmosphere (drainage, runoff, evapotranspiration). This role of soil as regulator/control of water fluxes, but also as a supporting medium to plant growth, is strongly dependent on the hydric properties of the soil. In turn, the plant roots growing in the soil can change its structure; both in the plow layer and in the deeper horizons and, therefore, could change the soil properties, particularly hydric properties. Such root-related alteration of soil properties can be linked to direct effect of roots such as soil perforation during growth, aggregation of soil particles or indirect effects such as the release of exudates by roots that could modify the properties of water or of soil particles. On an another hand, the rhizosphere, the zone around roots influenced by the activity of root and associated microorganisms, could have a high influence on hydric properties, particularly the water retention. To test if crops and plant roots rhizosphere may have a significant effect on water retention, we conducted various experiment from laboratory to field scales. In the lab, we tested different soil and species for rhizospheric effect on soil water retention. Variation in available water content (AWC) between bulk and rhizospheric soil varied from non-significant to a significant increase (to about 16% increase) depending on plant species and soil type. In the field, the alteration of water retention by root systems was tested in different pedological settings for a Maize crop inoculated or not with the bacteria Azospirillum spp., known to alter root structure, growth and morphology. Again, a range of variation in AWC was evidenced, with significant increase (~30%) in some soil types, but more linked to innoculated/non-innoculated plants rather than to a difference between rhizospheric and bulk soil. Finally, in field condition, on a larger time scale, we investigated the effect of crop alternations on the Lusignan ACBB SOERE site. That site presents on the same soil type different crop alternation treatments: an old, continuous grassland, a 8-year continuous cereal rotation and an alternation of cereal/grassland (3-years cereals and 3 to 6 years grassland). Measurements of AWC in these different crop systems setting, 8 years after implementation of the SOERE, show that AWC was different in the cereal/grassland alternation compared to the continuous cereal or grassland cropping systems (~15-20% increase). If such alteration of AWC may seem modest, modeling (in the case of ACBB SOERE) shows that this increase in AWC would increase the cereal yield but also decrease the water drainage out of the root zone, and the possible associated loss of nitrate and pesticides. As a conclusion, in line with some other literature data, roots can influence soil hydric properties and this opens a way to use plants as "soil engineers" to modulate the properties of the root zone, and thus the components of water balance, to mitigate effects of drought on crops… However, how and how much plants will modify the hydric properties, a question which mixes physics, biology, microbiology, crop system settings, is still in infancy and needs further research.

Effect of Different Peat Size and Pre-Consolidation Pressure of Reconstituted Peat on Effective Undrained Shear Strength Properties

NASA Astrophysics Data System (ADS)

Azhar, ATS; Norhaliza, W.; Ismail, B.; Ezree, AM; Nizam, ZM

2017-08-01

Shear strength of the soil is one of the most important parameters in engineering design, especially during the pre- or post-construction periods, since it is mainly used to measure and evaluate the foundation or slope stability of soil. Peat normally known as a soil that has a very low value of shear strength, and in order to determine and understand the shear strength of the peat, it is a difficult task in geotechnical engineering due to several factors such as types of fabrics, the origin of the soil, water content, organic matter and the degree of humification. The aim of this study is to determine the effective undrained shear strength properties of reconstituted peat of different sizes. All the reconstituted peat samples were formed with the size that passed the opening sieve of 0.425 mm (

Development of digital instructional modules for transportation engineers overviewing the fundamentals of how to obtain soil properties in practice.

DOT National Transportation Integrated Search

2013-12-01

The work completed in this project created a series of online lab modules that : transportation professionals could use as a reference to learn how to conduct, how to : interpret, and the applications of geotechnical lab tests used in practice to det...

Quaternary Geologic Map of the Regina 4 Degrees x 6 Degrees Quadrangle, United States and Canada

USGS Publications Warehouse

Fullerton, David S.; Christiansen, Earl A.; Schreiner, Bryan T.; Colton, Roger B.; Clayton, Lee; Bush, Charles A.; Fullerton, David S.

2007-01-01

For scientific purposes, the map differentiates Quaternary surficial deposits and materials on the basis of clast lithology or composition, matrix texture or particle size, structure, genesis, stratigraphic relations, engineering geologic properties, and relative age, as shown on the correlation diagram and indicated in the 'Description of Map Units'. Deposits of some constructional landforms, such as end moraines, are distinguished as map units. Deposits of erosional landforms, such as outwash terraces, are not distinguished, although glaciofluvial, ice-contact, fluvial, and lacustrine deposits that are mapped may be terraced. Differentiation of sequences of fluvial and glaciofluvial deposits at this scale is not possible. For practical purposes, the map is a surficial materials map. Materials are distinguished on the basis of lithology or composition, texture or particle size, and other physical, chemical, and engineering characteristics. It is not a map of soils that are recognized and classified in pedology or agronomy. Rather, it is a generalized map of soils as recognized in engineering geology, or of substrata or parent materials in which pedologic or agronomic soils are formed. As a materials map, it serves as a base from which a variety of maps for use in planning engineering, land-use planning, or land-management projects can be derived and from which a variety of maps relating to earth surface processes and Quaternary geologic history can be derived.

Stress transmission through a model system of cohesionless elastic grains

NASA Astrophysics Data System (ADS)

Da Silva, Miguel; Rajchenbach, Jean

2000-08-01

Understanding the mechanical properties of granular materials is important for applications in civil and chemical engineering, geophysical sciences and the food industry, as well as for the control or prevention of avalanches and landslides. Unlike continuous media, granular materials lack cohesion, and cannot resist tensile stresses. Current descriptions of the mechanical properties of collections of cohesionless grains have relied either on elasto-plastic models classically used in civil engineering, or on a recent model involving hyperbolic equations. The former models suggest that collections of elastic grains submitted to a compressive load will behave elastically. Here we present the results of an experiment on a two-dimensional model system-made of discrete square cells submitted to a point load-in which the region in which the stress is confined is photoelastically visualized as a parabola. These results, which can be interpreted within a statistical framework, demonstrate that the collective response of the pile contradicts the standard elastic predictions and supports a diffusive description of stress transmission. We expect that these findings will be applicable to problems in soil mechanics, such as the behaviour of cohesionless soils or sand piles.

Does mycorrhizal inoculation benefit plant survival, plant development and small-scale soil fixation? Results from a perennial eco-engineering field experiment in the Swiss Alps.

NASA Astrophysics Data System (ADS)

Bast, Alexander; Grimm, Maria; Graf, Frank; Baumhauer, Roland; Gärtner, Holger

2015-04-01

In mountain environments superficial slope failures on coarse grained, vegetation-free slopes are common processes and entail a certain risk for humans and socio-economic structures. Eco-engineering measures can be applied to mitigate slope instabilities. In this regard, limited plant survival and growth can be supported by mycorrhizal inoculation, which was successfully tested in laboratory studies. However, related studies on a field scale are lacking. Furthermore, mycorrhizae are known to enhance soil aggregation, which is linked to soil physics such as shear strength, and hence it is a useful indicator for near-surface soil/slope stability. The overall objective of our contribution was to test whether mycorrhizal inoculation can be used to promote eco-engineering measures in steep alpine environments based on a five-year field experiment. We hypothesized that mycorrhizal inoculation (i) enhances soil aggregation, (ii) stimulate plant survival and fine root development, (iii) effects plant performance, (iv) the stimulated root development in turn influences aggregate stability, and (v) that climatic variations play a major role in fine-root development. We established mycorrhizal and non-mycorrhizal treated eco-engineered research plots (hedge layers mainly consisting of Alnus spp. and Salix spp.) on a field experimental scale. The experimental site is in the eastern Swiss Alps at an erosion-prone slope where many environmental conditions can be seen as homogeneous. Soil aggregation, fine root development and plant survival was quantified at the end of four growing seasons (2010, '11, '12, '14). Additionally, growth properties of Alnus spp. and Salix spp. were measured and their biomass estimated. Meteorological conditions, soil temperature and soil water content were recorded. (i) The introduced eco-engineering measures enhanced aggregate stability significantly. In contrast to published greenhouse and laboratory studies, mycorrhizal inoculation delayed soil aggregate stabilization relative to the non-inoculated site but resulted in a significantly higher aggregate stability compared to the control and the non-inoculated site at the end of the third growing season. (ii) Plant survival was significantly improved by the inoculation. Fine-root development was stimulated but not immediately. At the end of the third growing season, root length density tended to be higher and mean root diameter was significantly increased at the mycorrhizal treated site. (iii) Analyses on plant performance of Alnus and Salix demonstrated that the inoculated saplings achieved significantly higher survival rates. There was no treatment effect on plant growth properties except in 2010, where plant height and main stem diameter of Alnus was increased at the mycorrhizal treated site. The estimated total biomass of Alnus and Salix was higher at the mycorrhizal treated site. (iv) There was a positive correlation between root length density and aggregate stability, whereas roots < 0.5 mm were most influential on aggregate stability. (v) Interannual climatic variations seem to have a crucial influence on root development and, hence, on slope stability. There is a temporal offset of two growing seasons between inoculation effects tested in greenhouse/laboratory and the presented field experiment. However, the application of a commercial mycorrhizal inoculum in eco-engineering measures is a beneficial promoter to mitigate slope instability and surface erosion but needs to be tested at other sites. The contribution is mainly based on Bast (2014) and was funded by the Wolfermann Nägeli Stiftung Zürich and the Swiss Federal Office for Environment (BAFU No.: 09.0027.PJ/I211-3446). Bast, A. (2014): Mycorrhizal inoculation as a promoter for sustainable eco-engineering measures in steep alpine environments? Results of a three-year field experiment in the Arieschbach catchment, Fideris, eastern Swiss Alps. PhD Thesis. University of Berne: 149pp.

Experimental studies on the physico-mechanical properties of jet-grout columns in sandy and silty soils

NASA Astrophysics Data System (ADS)

Akin, Muge K.

2016-04-01

The term of ground improvement states to the modification of the engineering properties of soils. Jet-grouting is one of the grouting methods among various ground improvement techniques. During jet-grouting, different textures of columns can be obtained depending on the characteristics of surrounding subsoil as well as the adopted jet-grouting system for each site is variable. In addition to textural properties, strength and index parameters of jet-grout columns are highly affected by the adjacent soil. In this study, the physical and mechanical properties of jet-grout columns constructed at two different sites in silty and sandy soil conditions were determined by laboratory tests. A number of statistical relationships between physical and mechanical properties of soilcrete were established in this study in order to investigate the dependency of numerous variables. The relationship between qu and γd is more reliable for sandy soilcrete than that of silty columns considering the determination coefficients. Positive linear relationships between Vp and γd with significantly high determination coefficients were obtained for the jet-grout columns in silt and sand. The regression analyses indicate that the P-wave velocity is a very dominant parameter for the estimation of physical and mechanical properties of jet-grout columns and should be involved during the quality control of soilcrete material despite the intensive use of uniaxial compressive strength test. Besides, it is concluded that the dry unit weight of jet-grout column is a good indicator of the efficiency of employed operational parameters during jet-grouting.

Infiltration into soils: Conceptual approaches and solutions

NASA Astrophysics Data System (ADS)

Assouline, Shmuel

2013-04-01

Infiltration is a key process in aspects of hydrology, agricultural and civil engineering, irrigation design, and soil and water conservation. It is complex, depending on soil and rainfall properties and initial and boundary conditions within the flow domain. During the last century, a great deal of effort has been invested to understand the physics of infiltration and to develop quantitative predictors of infiltration dynamics. Jean-Yves Parlange and Wilfried Brutsaert have made seminal contributions, especially in the area of infiltration theory and related analytical solutions to the flow equations. This review retraces the landmark discoveries and the evolution of the conceptual approaches and the mathematical solutions applied to the problem of infiltration into porous media, highlighting the pivotal contributions of Parlange and Brutsaert. A historical retrospective of physical models of infiltration is followed by the presentation of mathematical methods leading to analytical solutions of the flow equations. This review then addresses the time compression approximation developed to estimate infiltration at the transition between preponding and postponding conditions. Finally, the effects of special conditions, such as the presence of air and heterogeneity in soil properties, on infiltration are considered.

Biological Soil Crusts from Coastal Dunes at the Baltic Sea: Cyanobacterial and Algal Biodiversity and Related Soil Properties.

PubMed

Schulz, Karoline; Mikhailyuk, Tatiana; Dreßler, Mirko; Leinweber, Peter; Karsten, Ulf

2016-01-01

Biological soil crusts (BSCs) are known as "ecosystem-engineers" that have important, multifunctional ecological roles in primary production, in nutrient and hydrological cycles, and in stabilization of soils. These communities, however, are almost unstudied in coastal dunes of the temperate zone. Hence, for the first time, the biodiversity of cyanobacterial and algal dominated BSCs collected in five dunes from the southern Baltic Sea coast on the islands Rügen and Usedom (Germany) was investigated in connection with physicochemical soil parameters. The species composition of cyanobacteria and algae was identified with direct determination of crust subsamples, cultural methods, and diatom slides. To investigate the influence of soil properties on species composition, the texture, pH, electrical conductivity, carbonate content, total contents of carbon, nitrogen, phosphorus, and the bioavailable phosphorus-fraction (PO4 (3-)) were analyzed in adjacent BSC-free surface soils at each study site. The data indicate that BSCs in coastal dunes of the southern Baltic Sea represent an ecologically important vegetation form with a surprisingly high site-specific diversity of 19 cyanobacteria, 51 non-diatom algae, and 55 diatoms. All dominant species of the genera Coleofasciculus, Lyngbya, Microcoleus, Nostoc, Hydrocoryne, Leptolyngbya, Klebsormidium, and Lobochlamys are typical aero-terrestrial cyanobacteria and algae, respectively. This first study of coastal sand dunes in the Baltic region provides compelling evidence that here the BSCs were dominated by cyanobacteria, algae, or a mixture of both. Among the physicochemical soil properties, the total phosphorus content of the BSC-free sand was the only factor that significantly influenced the cyanobacterial and algal community structure of BSCs in coastal dunes.

Clay-cement suspensions - rheological and functional properties

NASA Astrophysics Data System (ADS)

Wojcik, L.; Izak, P.; Mastalska-Poplawska, J.; Gajek, M.

2017-01-01

The piping erosion in soil is highly unexpected in civil engineering. Elimination of such damages is difficult, expensive and time-consuming. One of the possibility is the grouting method. This method is still developed into direction of process automation as well as other useful properties of suspensions. Main way of modernization of the grouting method is connected it with rheology of injection and eventuality of fitting them to specific problems conditions. Very popular and useful became binders based on modified clays (clay-cement suspensions). Important principle of efficiency of the grouting method is using of time-dependent pseudothixotropic properties of the clay-cement suspensions. The pseudo-rheounstability aspect of the suspensions properties should be dedicated and fitted to dynamic changes of soil conditions destructions. Whole process of the modification of the suspension rheology is stimulated by the specific agents. This article contains a description of practical aspects of the rheological parameters managing of the clay-cement suspensions, dedicated to the building damages, hydrotechnic constructions etc.

"Dirt Cheap" Project Teaches Soils Engineering

ERIC Educational Resources Information Center

Roman, Harry T.

2010-01-01

This article describes a soil-testing activity that enables students to learn some interesting and useful things about how soil behaves under varied conditions. It offers a great way to give them a practical pre-engineering experience and will show them how engineers think about construction and how local soils influence building design. The…

Engineering geological mapping in Wallonia (Belgium) : present state and recent computerized approach

NASA Astrophysics Data System (ADS)

Delvoie, S.; Radu, J.-P.; Ruthy, I.; Charlier, R.

2012-04-01

An engineering geological map can be defined as a geological map with a generalized representation of all the components of a geological environment which are strongly required for spatial planning, design, construction and maintenance of civil engineering buildings. In Wallonia (Belgium) 24 engineering geological maps have been developed between the 70s and the 90s at 1/5,000 or 1/10,000 scale covering some areas of the most industrialized and urbanized cities (Liège, Charleroi and Mons). They were based on soil and subsoil data point (boring, drilling, penetration test, geophysical test, outcrop…). Some displayed data present the depth (with isoheights) or the thickness (with isopachs) of the different subsoil layers up to about 50 m depth. Information about geomechanical properties of each subsoil layer, useful for engineers and urban planners, is also synthesized. However, these maps were built up only on paper and progressively needed to be updated with new soil and subsoil data. The Public Service of Wallonia and the University of Liège have recently initiated a study to evaluate the feasibility to develop engineering geological mapping with a computerized approach. Numerous and various data (about soil and subsoil) are stored into a georelational database (the geotechnical database - using Access, Microsoft®). All the data are geographically referenced. The database is linked to a GIS project (using ArcGIS, ESRI®). Both the database and GIS project consist of a powerful tool for spatial data management and analysis. This approach involves a methodology using interpolation methods to update the previous maps and to extent the coverage to new areas. The location (x, y, z) of each subsoil layer is then computed from data point. The geomechanical data of these layers are synthesized in an explanatory booklet joined to maps.

Water Drainage from Unsaturated Soils in a Centrifuge Permeameter

NASA Astrophysics Data System (ADS)

Ornelas, G.; McCartney, J.; Zhang, M.

2013-12-01

This study involves an analysis of water drainage from an initially saturated silt layer in a centrifuge permeameter to evaluate the hydraulic properties of the soil layer in unsaturated conditions up to the point where the water phase becomes discontinuous. These properties include the soil water retention curve (SWRC) and the hydraulic conductivity function (HCF). The hydraulic properties of unsaturated silt are used in soil-atmosphere interaction models that take into account the role of infiltration and evaporation of water from soils due to atmospheric interaction. These models are often applied in slope stability analyses, landfill cover design, aquifer recharge analyses, and agricultural engineering. The hydraulic properties are also relevant to recent research concerning geothermal heating and cooling, as they can be used to assess the insulating effects of soil around underground heat exchangers. This study employs a high-speed geotechnical centrifuge to increase the self-weight of a compacted silt specimen atop a filter plate. Under a centrifuge acceleration of N times earth's gravity, the concept of geometric similitude indicates that the water flow process in a small-scale soil layer will be similar to those in a soil layer in the field that is N times thicker. The centrifuge acceleration also results in an increase in the hydraulic gradient across the silt specimen, which causes water to flow out of the pores following Darcy's law. The drainage test was performed until the rate of liquid water flow out of the soil layer slowed to a negligible level, which corresponds to the transition point at which further water flow can only occur due to water vapor diffusion following Fick's law. The data from the drainage test in the centrifuge were used to determine the SWRC and HCF at different depths in the silt specimen, which compared well with similar properties defined using other laboratory tests. The transition point at which liquid water flow stopped (and Darcy's law is no longer valid) was at a relatively high degree of saturation of 0.8. This finding is important as many water flow analyses in the literature assume that Darcy's law is valid over a much wider range of degrees of saturation, an error that potentially may lead to overestimates of water flow in unsaturated soil layers.

A History of Soil Science Education in the United States

NASA Astrophysics Data System (ADS)

Brevik, Eric C.

2017-04-01

The formal study of soil science is a fairly recent undertaking in academics. Fields like biology, chemistry, and physics date back hundreds of years, but the scientific study of soils only dates to the late 1800s. Academic programs to train students in soil science are even more recent, with the first such programs only developing in the USA in the early 1900s. Some of the first schools to offer soil science training at the university level included the University of North Carolina (UNC), Earlham College (EC), and Cornell University. The first modern soil science textbook published in the United States was "Soils, Their Properties and Management" by Littleton Lyon, Elmer Fippin and Harry Buckman in 1909. This has evolved over time into the popular modern textbook "The Nature and Properties of Soils", most recently authored by Raymond Weil and Nyle Brady. Over time soil science education moved away from liberal arts schools such as UNC and EC and became associated primarily with land grant universities in their colleges of agriculture. There are currently about 71 colleges and universities in the USA that offer bachelors level soil science degree programs, with 54 of these (76%) being land grant schools. In the 1990s through the early 2000s enrollment in USA soil science programs was on the decline, even as overall enrollment at USA colleges and universities increased. This caused considerable concern in the soil science community. More recently there is evidence that soil science student numbers may be increasing, although additional information on this potential trend is desirable. One challenge soil science faces in the modern USA is finding an academic home, as soils are taught by a wide range of fields and soils classes are taken by students in many fields of study, including soil science, a range of agricultural programs, environmental science, environmental health, engineering, geology, geography, and others.

Geological Engineering Characteristics of the Residual Soil: Implementation for Soil Bearing Capacity at Gayungan, Surabaya, East Java

NASA Astrophysics Data System (ADS)

Rukmana, Y. Y.; Ridwan, M.

2018-01-01

This paper presents the results of soil investigation on the residual soil at Gayungan Surabaya. The methodology of the research consists of Drilling + Standard Penetration Test (ASTM D1586-99), sampling and laboratory test for index properties & mechanical of soil, then analyzed for Soil Bearing Capacity (Meyerhoff, 1976). Field test analysis data showed that Bore Hole.01(BH.01) and Bore Hole.03 (BH.03) were dominated by Sand / Sandy clay layer with Standart Penetration Test (SPT) values: 6-68, whereas in BH.02 was dominated by Clayey sand layer with Standard Penetration Test (SPT) values: 32-68. Based on Soil classification according to Unified Soil Classification System (USCS), the soil type at the research area consisted of ML (Silt with Low plasticity), CL ( Clay with low plasticity), MH (Silt with High plasticity), and SP (Sand with Poor gradation). Based on the borlog data and soil bearing capacity analysis of the research area is recommended: for The Deep foundation to reaches at least 16 meters depth with Qa = 1160.40-2032.80 kN / m2, and Shallow foundation reaches at least 1-2 meters deep with Qa = 718.25 kN / M2.

Soil temperature of peatland landscapes as a factor in the development of exogenous processes of biogenic relief formation in engineering development of territory

NASA Astrophysics Data System (ADS)

Korkin, S.; Talyneva, O.; Kail, E.

2018-03-01

In the presented work we consider mire landscapes in the context of temperature monitoring. The mire landscapes in engineering development of the territory are very sensitive to anthropogenic impact that leads to a change in surface conditions, changes in natural succession and, as a rule, to changes in soil temperature and properties, which in turn may develop a complex of hostile geodynamic processes. For this study we used recording systems for field measurement of peat and subsoil temperatures. The measurements were made in two key areas: the territory of the north-taiga landscapes of Western Siberia (the Siberian Ridges), and the territory of the middle-taiga landscapes of Western Siberia (the Ob middle-river lowland). The paper analyses the data obtained from five observation sites (3, 5, 5a, 6 and 8) referred to hydromorphic landscapes. For the territory of the Siberian Ridges the 5-year average soil temperature was 3°C. For the Ob middle-river lowland the 6-year average soil temperature was 4.2°C. The annual soil temperature in the period 2015-2016 for Site 5a (man-disturbed area) was 8.3°C at all depths, which is 3.8°C higher than in a natural bog (Site 5 was a control area).

Compendium of Abstracts on Statistical Applications in Geotechnical Engineering.

DTIC Science & Technology

1983-09-01

research in the application of probabilistic and statistical methods to soil mechanics, rock mechanics, and engineering geology problems have grown markedly...probability, statistics, soil mechanics, rock mechanics, and engineering geology. 2. The purpose of this report is to make available to the U. S...Deformation Dynamic Response Analysis Seepage, Soil Permeability and Piping Earthquake Engineering, Seismology, Settlement and Heave Seismic Risk Analysis

A State-of-the-Art Review on Soil Reinforcement Technology Using Natural Plant Fiber Materials: Past Findings, Present Trends and Future Directions.

PubMed

Gowthaman, Sivakumar; Nakashima, Kazunori; Kawasaki, Satoru

2018-04-04

Incorporating sustainable materials into geotechnical applications increases day by day due to the consideration of impacts on healthy geo-environment and future generations. The environmental issues associated with conventional synthetic materials such as cement, plastic-composites, steel and ashes necessitate alternative approaches in geotechnical engineering. Recently, natural fiber materials in place of synthetic material have gained momentum as an emulating soil-reinforcement technique in sustainable geotechnics. However, the natural fibers are innately different from such synthetic material whereas behavior of fiber-reinforced soil is influenced not only by physical-mechanical properties but also by biochemical properties. In the present review, the applicability of natural plant fibers as oriented distributed fiber-reinforced soil (ODFS) and randomly distributed fiber-reinforced soil (RDFS) are extensively discussed and emphasized the inspiration of RDFS based on the emerging trend. Review also attempts to explore the importance of biochemical composition of natural-fibers on the performance in subsoil reinforced conditions. The treatment methods which enhances the behavior and lifetime of fibers, are also presented. While outlining the current potential of fiber reinforcement technology, some key research gaps have been highlighted at their importance. Finally, the review briefly documents the future direction of the fiber reinforcement technology by associating bio-mediated technological line.

A State-of-the-Art Review on Soil Reinforcement Technology Using Natural Plant Fiber Materials: Past Findings, Present Trends and Future Directions

PubMed Central

Gowthaman, Sivakumar; Nakashima, Kazunori; Kawasaki, Satoru

2018-01-01

Incorporating sustainable materials into geotechnical applications increases day by day due to the consideration of impacts on healthy geo-environment and future generations. The environmental issues associated with conventional synthetic materials such as cement, plastic-composites, steel and ashes necessitate alternative approaches in geotechnical engineering. Recently, natural fiber materials in place of synthetic material have gained momentum as an emulating soil-reinforcement technique in sustainable geotechnics. However, the natural fibers are innately different from such synthetic material whereas behavior of fiber-reinforced soil is influenced not only by physical-mechanical properties but also by biochemical properties. In the present review, the applicability of natural plant fibers as oriented distributed fiber-reinforced soil (ODFS) and randomly distributed fiber-reinforced soil (RDFS) are extensively discussed and emphasized the inspiration of RDFS based on the emerging trend. Review also attempts to explore the importance of biochemical composition of natural-fibers on the performance in subsoil reinforced conditions. The treatment methods which enhances the behavior and lifetime of fibers, are also presented. While outlining the current potential of fiber reinforcement technology, some key research gaps have been highlighted at their importance. Finally, the review briefly documents the future direction of the fiber reinforcement technology by associating bio-mediated technological line. PMID:29617285

Geotechnical characterization of mined clay from Appalachian Ohio: challenges and implications for the clay mining industry.

PubMed

Moran, Anthony R; Hettiarachchi, Hiroshan

2011-07-01

Clayey soil found in coal mines in Appalachian Ohio is often sold to landfills for constructing Recompacted Soil Liners (RSL) in landfills. Since clayey soils possess low hydraulic conductivity, the suitability of mined clay for RSL in Ohio is first assessed by determining its clay content. When soil samples are tested in a laboratory, the same engineering properties are typically expected for the soils originated from the same source, provided that the testing techniques applied are standard, but mined clay from Appalachian Ohio has shown drastic differences in particle size distribution depending on the sampling and/or laboratory processing methods. Sometimes more than a 10 percent decrease in the clay content is observed in the samples collected at the stockpiles, compared to those collected through reverse circulation drilling. This discrepancy poses a challenge to geotechnical engineers who work on the prequalification process of RSL material as it can result in misleading estimates of the hydraulic conductivity of the samples. This paper describes a laboratory investigation conducted on mined clay from Appalachian Ohio to determine how and why the standard sampling and/or processing methods can affect the grain-size distributions. The variation in the clay content was determined to be due to heavy concentrations of shale fragments in the clayey soils. It was also concluded that, in order to obtain reliable grain size distributions from the samples collected at a stockpile of mined clay, the material needs to be processed using a soil grinder. Otherwise, the samples should be collected through drilling.

Geotechnical Characterization of Mined Clay from Appalachian Ohio: Challenges and Implications for the Clay Mining Industry

PubMed Central

Moran, Anthony R.; Hettiarachchi, Hiroshan

2011-01-01

Clayey soil found in coal mines in Appalachian Ohio is often sold to landfills for constructing Recompacted Soil Liners (RSL) in landfills. Since clayey soils possess low hydraulic conductivity, the suitability of mined clay for RSL in Ohio is first assessed by determining its clay content. When soil samples are tested in a laboratory, the same engineering properties are typically expected for the soils originated from the same source, provided that the testing techniques applied are standard, but mined clay from Appalachian Ohio has shown drastic differences in particle size distribution depending on the sampling and/or laboratory processing methods. Sometimes more than a 10 percent decrease in the clay content is observed in the samples collected at the stockpiles, compared to those collected through reverse circulation drilling. This discrepancy poses a challenge to geotechnical engineers who work on the prequalification process of RSL material as it can result in misleading estimates of the hydraulic conductivity of the samples. This paper describes a laboratory investigation conducted on mined clay from Appalachian Ohio to determine how and why the standard sampling and/or processing methods can affect the grain-size distributions. The variation in the clay content was determined to be due to heavy concentrations of shale fragments in the clayey soils. It was also concluded that, in order to obtain reliable grain size distributions from the samples collected at a stockpile of mined clay, the material needs to be processed using a soil grinder. Otherwise, the samples should be collected through drilling. PMID:21845150

Proposal and Research Direction of Soil Mass Organic Reorganization

NASA Astrophysics Data System (ADS)

Zhang, Lu; Han, Jichang

2018-01-01

Land engineering as a new discipline has been temporarily outrageous. The proposition of soil body organic reorganization undoubtedly enriches the research content for the construction of land engineering disciplines. Soil body organic reconstruction is designed to study how to realize the ecological ecology of the land by studying the external force of nature, to study the influence of sunlight, wind and water on soil body, how to improve the soil physical structure, to further strengthen the research of biological enzymes and microbes, and promote the release and utilization of beneficial inert elements in soil body. The emerging of frontier scientific research issues with soil body organic reorganization to indicate directions for the future development of soil engineering.

The Impact of Soil Properties on Valley-Bottom Gully Form, Northwest Highlands of Ethiopia.

NASA Astrophysics Data System (ADS)

Amare, S. D.; Langendoen, E. J.; Keesstra, S.; van der Ploeg, M. J.; Steenhuis, T. S.; Tilahun, S. A.

2017-12-01

Gully erosion is an important environmental and food security challenge facing the world. Despite the immense damages resulting from gully erosion, comprehensive studies on the processes of gully formation and its management strategies are limited. This is especially true for valley-bottom gullies, which form under different conditions and are caused by different processes than hillslope gullies. A recent review on valley-bottom gully erosion causes and controlling factors identified that gully geomorphological processes, particularly related to gully bank retreat, governed gully occurrence and reclamations. However, most valley-bottom gully erosion studies do not consider gully bank stability and how it is impacted by soil hydrology and soil intrinsic properties. The aim is to analyze these impacts on gully bank retreat in the Koga river watershed, Ethiopia, for Nitisol and Vertisols, using field and numerical modeling approaches. Field observations showed gully network in Vertisols were greater than those in Nitisols. On the other hand, Nitisol gullies are wider and deeper than Vertisols. Monitoring of hydro-meteorological and soil data was started in June 2017 and will continue until the end of the 2017 rainy season (September) and for 2018 rainy periods as well. Thirty-six piezometers were installed at 4m average depth covering an area of 20 km2 near the gully reaches. Ground anchors were used to measure soil swelling and shrinkage. Soil moisture content and potential were measured using GS1 Soil Moisture sensors and MPS-6 Water Potential sensors. Gully bank soil physicochemical and engineering properties have been sampled and analyzed. Preliminary results from the early portion of the rainy season showed that most piezometers were already filled up with water. However, relatively deep (2m) water tables were recorded in piezometers located near the gully banks. The soil matric potential dropped from the onset of the rainy season (-6800 kPa ) towards the middle (-6 kPa), while soil moisture content increased from 30% to 50%.The field data will be used as input for the BSTEM bank erosion model. BSTEM will be used to evaluate and quantify the effects of soil physical properties on gully form. The modeling results will be presented and will serve to develop improved reclamation strategies of valley-bottom gullies.

Road Maintenance Experience Using Polyurethane (PU) Foam Injection System and Geocrete Soil Stabilization as Ground Rehabilitation

NASA Astrophysics Data System (ADS)

Fakhar, A. M. M.; Asmaniza, A.

2016-07-01

There are many types of ground rehabilation and improvement that can be consider and implement in engineering construction works for soil improvement in order to prevent road profile deformation in later stage. However, when comes to road maintenance especially on operated expressways, not all method can be apply directly as it must comply to opreation's working window and lane closure basis. Key factors that considering ideal proposal for ground rehabilitation are time, cost, quality and most importantly practicality. It should provide long lifespan structure in order to reduce continuous cycle of maintenance. Thus, this paper will present two approaches for ground rehabilitation, namely Polyurethane (PU) Foam Injection System and Geocrete Soil Stabilization. The first approach is an injection system which consists two-parts chemical grout of Isocynate and Polyol when mixed together within soil structure through injection will polymerized with volume expansion. The strong expansion of grouting causes significant compression and compacting of the surrounding soil and subsequently improve ground properties and uplift sunken structure. The later is a cold in-place recyclying whereby mixture process that combines in-situ soil materials, cement, white powder (alkaline) additive and water to produce hard yet flexible and durable ground layer that act as solid foundation with improved bearing capacity. The improvement of the mechanical behaviour of soil through these two systems is investigated by an extensive testing programme which includes in-situ and laboratory test in determining properties such as strength, stiffness, compressibility, bearing capacity, differential settlement and etc.

A study of Ground Source Heat Pump based on a heat infiltrates coupling model established with FEFLOW

NASA Astrophysics Data System (ADS)

Chen, H.; Hu, C.; Chen, G.; Zhang, Q.

2017-12-01

Geothermal heat is a viable source of energy and its environmental impact in terms of CO2 emissions is significantly lower than conventional fossil fuels. it is vital that engineers acquire a proper understanding about the Ground Source Heat Pump (GSHP). In this study, the model of the borehole exchanger under conduction manners and heat infiltrates coupling manners was established with FEFLOW. The energy efficiency, heat transfer endurance and heat transfer in the unit depth were introduced to quantify the energy efficient and the endurance period. The performance of a the Borehole Exchanger (BHE) in soil with and without groundwater seepage was analyzed of heat transfer process between the soil and the working fluid. Basing on the model, the varied regularity of energy efficiency performance an heat transfer endurance with the conditions including the different configuration of the BHE, the soil properties, thermal load characteristic were discussed. Focus on the heat transfer process in multi-layer soil which one layer exist groundwater flow. And an investigation about thermal dispersivity was also analyzed its influence on heat transfer performance. The final result proves that the model of heat infiltrates coupling model established in this context is reasonable, which can be applied to engineering design.

Coupled Electro-Hydrodynamic Effects of Electro-Osmosis from Pore Scale to Darcy Scale

NASA Astrophysics Data System (ADS)

Schotting, R.; Joekar-Niasar, V.; Leijnse, A.

2011-12-01

Electro-osmosis is "movement of a fluid under the effect of an electric field in a porous medium". This phenomenon has many applications in civil engineering (slope stabilization, dewatering), environmental engineering (soil remediation, sludge dewatering), chemical engineering (micro- or nano- mixers), medical engineering (drug delivery), etc. The key factor in electro-osmosis is the competition between the electrochemical and hydrodynamic forces as well as the coupling between the solid surface and the electrolyte properties. The objective of this research is to understand the influence of pore-scale heterogeneities of surface properties on the Darcy-scale behavior. We develop novel analytical solutions for the flow and transport of electrolyte including electro-hydrodynamic forces in a single micro-channel. We propose the complete analytical solution for monovalent electrolyte at full range overlapping double layers, and nonlinear electric field, including the Donan effect in transport of ions. These pore-scale formulations are numerically upscaled to obtain the Darcy-scale behavior. Our results show the contribution of electro-osmotic, chemical-osmotic and hydrodynamic components of the flow equation on pressure field evolution and multi-directional flow field at Darcy scale.

CF60 Concrete Composition Design and Application on Fudiankou Xijiang Super Large Bridge

NASA Astrophysics Data System (ADS)

Qiu, Yi Mei; Wen, Sen Yuan; Chen, Jun Xiang

2018-06-01

Guangxi Wuzhou City Ring Road Fudiankou Xijiang super large bridge CF60 concrete is a new multi-phase composite high-performance concrete, this paper for the Fudiankou Xijiang bridge structure and characteristics of the project, in accordance with the principle of local materials and technical specification requirements, combined with the site conditions of CF60 engineering high performance concrete component materials, proportion and the technical performance, quantify the main physical and mechanical performance index. Analysis main influencing factors of the technical indicators, reasonable adjustment of concrete mix design parameters, and the use of technical means of admixture and multi-function composite admixture of concrete, obtain the optimal proportion of good work, process, mechanical properties stability and durability of engineering properties, recommend and verification of concrete mix; to explore the CF60 high performance concrete Soil in the Fudiankou Xijiang bridge application technology, detection and tracking the quality of concrete construction, concrete structure during the construction of the key technology and control points is proposed, evaluation of CF60 high performance concrete in the actual engineering application effect and benefit to ensure engineering quality of bridge structure and service life, and super long span bridge engineering construction to provide basis and reference.

Soil as natural heat resource for very shallow geothermal application: laboratory and test site updates from ITER Project

NASA Astrophysics Data System (ADS)

Di Sipio, Eloisa; Bertermann, David

2017-04-01

Nowadays renewable energy resources for heating/cooling residential and tertiary buildings and agricultural greenhouses are becoming increasingly important. In this framework, a possible, natural and valid alternative for thermal energy supply is represented by soils. In fact, since 1980 soils have been studied and used also as heat reservoir in geothermal applications, acting as a heat source (in winter) or sink (in summer) coupled mainly with heat pumps. Therefore, the knowledge of soil thermal properties and of heat and mass transfer in the soils plays an important role in modeling the performance, reliability and environmental impact in the short and long term of engineering applications. However, the soil thermal behavior varies with soil physical characteristics such as soil texture and water content. The available data are often scattered and incomplete for geothermal applications, especially very shallow geothermal systems (up to 10 m depths), so it is worthy of interest a better comprehension of how the different soil typologies (i.e. sand, loamy sand...) affect and are affected by the heat transfer exchange with very shallow geothermal installations (i.e. horizontal collector systems and special forms). Taking into consideration these premises, the ITER Project (Improving Thermal Efficiency of horizontal ground heat exchangers, http://iter-geo.eu/), funded by European Union, is here presented. An overview of physical-thermal properties variations under different moisture and load conditions for different mixtures of natural material is shown, based on laboratory and field test data. The test site, located in Eltersdorf, near Erlangen (Germany), consists of 5 trenches, filled in each with a different material, where 5 helix have been installed in an horizontal way instead of the traditional vertical option.

Developing a High Fidelity Martian Soil Simulant Based on MSL Measurements: Applications for Habitability, Exploration, and In-Situ Resource Utilization

NASA Astrophysics Data System (ADS)

Cannon, K.; Britt, D. T.; Smith, T. M.; Fritsche, R. F.; Covey, S. D.; Batcheldor, D.; Watson, B.

2017-12-01

Powerful instruments, that include CheMin and SAM on the MSL Curiosity rover, have provided an unprecedented look into the mineral, chemical, and volatile composition of Martian soils. Interestingly, the bulk chemistry of the Rocknest windblown soil is a close match to similar measurements from the Spirit and Opportunity rovers, suggesting the presence of a global basaltic soil component. The Martian regolith is likely composed of this global soil mixed with locally to regionally derived components that include alteration products and evolved volcanic compositions. Without returned soil samples, researchers have relied on terrestrial simulants to address fundamental Mars science, habitability, in-situ resource utilization, and hardware for future exploration. However, these past simulants have low fidelity compared to actual Martian soils: JSC Mars-1a is an amorphous palagonitic material with spectral similarities to Martian dust, not soil, and Mojave Mars is simply a ground up terrestrial basalt chosen for its convenient location. Based on our experience creating asteroid regolith simulants, we are developing a high fidelity Martian soil simulant (Mars Global) designed ab initio to match the mineralogy, chemistry, and volatile contents of the global basaltic soil on Mars. The crystalline portion of the simulant is based on CheMin measurements of Rocknest and includes plagioclase, two pyroxenes, olivine, hematite, magnetite, anhydrite, and quartz. The amorphous portion is less well constrained, but we are re-creating it with basaltic glass, synthetic ferrihydrite, ferric sulfate, and carbonates. We also include perchlorate and nitrate salts based on evolved gas analyses from the SAM instrument. Analysis and testing of Mars Global will include physical properties (shear strength, density, internal friction angle), spectral properties, magnetic properties, and volatile release patterns. The simulant is initially being designed for NASA agricultural studies, but applications include studies of habitability, toxicity, and in-situ resource utilization, among others. Through a partnership with Deep Space Industries we intend to produce industrial quantities of Mars Global from consistently maintained feedstocks, making it available to researchers, engineers, and educators.

An experimental study on stabilization of Pekan clay using polyethylene and polypropylene

NASA Astrophysics Data System (ADS)

Zukri, Azhani; Nazir, Ramli; Mender, Fatin Nabilah

2017-10-01

Many countries are expressing concern over the growing issues of polyethylene terephthalate (PET) bottles and polypropylene (PP) products made by the household sector. The rapid increase in the generation of plastic waste all around the world is due to the economic development and population growth. PP is the world's second-most widely produced synthetic plastic, after polyethylene. Statistics show that nearly 50% of the municipal solid waste in Malaysia comes from the institutional, industrial, residential, and construction waste. This paper presents the results of an investigation on the utilisation of fibres as products of PET bottles and PP products in order to improve the engineering properties of clay soil in Pekan. The soil samples were taken from Kampung Tanjung Medang, Pekan, Pahang. The basic properties of the clay soil were determined as follows; optimum moisture content: 32.5%, maximum dry density: 13.43 kN/m3, specific gravity: 2.51, liquid limit: 74.67%, plastic limit: 45.98%, and plasticity index: 28.69%. This investigation concentrates on the shear strength of the reinforced clay soils with PET and PP in random orientation. The reinforced soil samples were subjected to unconfined compression test (UCT) to differentiate their shear strength with that of the unreinforced soil. The tests found that the waste fibres (PET and PP) improved the strength properties of the Pekan clayey soils. The unconfined compressive strength (UCS) value increased with the increasing percentage of PET fibre and reached the optimum content at 10% reinforcement, where it showed the highest improvement of 365 kN/m2 from 325 kN/m2 and depleted when the optimum content reached 20% reinforcement. For PP fibre, the reinforced soil showed the highest UCS at 20% reinforcement with the improvement of 367 kN/m2. The study concluded that the PET and PP fibres can be utilised successfully as reinforcement materials for the stabilisation of clayey soils. The use of these waste compounds as alternative materials for clay soil stabilisation is reasonable and cost effective since they are constantly available.

DEMONSTRATION BULLETIN: NEW YORK STATE MULTI-VENDOR BIOREMEDIATION - ENSR CONSULTING AND ENGINEERING/LARSEN ENGINEERS EX-SITU BIOVAULT

EPA Science Inventory

The ENSR Biovault Treatment Process is an ex-situ bioremediation technology for the treatment of organic contaminated soils. Contaminated soils placed in specially designed soil piles, referred to as biovaults, are remediated by stimulating the indigenous soil microbes to prolife...

Soils and Foundations: A Syllabus.

ERIC Educational Resources Information Center

Long, Melvin J.

The teaching guide and course outline for a 12-week course in soils and foundations is designed to help student technicians in a two-year associate degree civil engineering technology program to obtain entry level employment as highway engineering aides, soil testing technicians, soil mappers, or construction inspectors. The seven teaching units…

Bioremediation of engine oil polluted soil by the tropical white rot fungus, Lentinus squarrosulus Mont. (Singer).

PubMed

Adenipekun, Clementina O; Isikhuemhen, Omoanghe S

2008-06-15

This study was conducted to test the efficacy of an indigenous white rot fungus Lentinus squarrosulus in degrading engine oil in soil. Flasks containing sterilized garden soil (100 g) moistened with 75% distilled water (w/v) were contaminated with engine oil 1, 2.5, 5, 10, 20 and 40% w/w concentrations, inoculated with L. squarrosulus and incubated at room temperature for 90 days. Levels of organic matter, pH, total hydrocarbon and elemental content (C, Cu, Fe, K, N, Ni, Zn and available P) were determined post-fungal treatment. Results indicate that contaminated soils inoculated with L. squarrosulus had increased organic matter, carbon and available phosphorus, while the nitrogen and available potassium was reduced. A relatively high percentage degradation of Total Petroleum Hydrocarbon (TPH) was observed at 1% engine oil concentration (94.46%), which decreased to 64.05% TPH degradation at 40% engine oil contaminated soil after 90 days of incubation. The concentrations of Fe, Cu, Zn and Ni recovered from straw/fungal biomass complex increased with the increase of engine-oil contamination and bio-accumulation by the white-rot fungus. The improvement of nutrient content values as well as the bioaccumulation of heavy metals at all levels of engine oil concentrations tested through inoculations with L. squarrosulus is of importance for the bioremediation of engine-oil polluted soils.

Soil hydrological and soil property changes resulting from termite activity on agricultural fields in Burkina Faso

NASA Astrophysics Data System (ADS)

Mettrop, I.; Cammeraat, L. H.; Verbeeten, E.

2009-04-01

Termites are important ecosystem-engineers in subtropical and tropical regions. The effect of termite activity affecting soil infiltration is well documented in the Sahelian region. Most studies find increased infiltration rates on surfaces that are affected by termite activity in comparison to crusted areas showing non-termite presence. Crusted agricultural fields in the Sanmatenga region in Burkina Faso with clear termite activity were compared to control fields without visual ground dwelling termite activity. Fine scale rainfall simulations were carried out on crusted termite affected and control sites. Furthermore soil moisture change, bulk density, soil organic matter as well as general soil characteristics were studied. The top soils in the study area were strongly crusted (structural crust) after the summer rainfall and harvest of millet. They have a loamy sand texture underlain by a shallow sandy loam Bt horizon. The initial soil moisture conditions were significantly higher on the termite plots when compared to control sites. It was found that the amount of runoff produced on the termite plots was significantly higher, and also the volumetric soil moisture content after the experiments was significantly lower if compared to the control plots. Bulk density showed no difference whereas soil organic matter was significantly higher under termite affected areas, in comparison to the control plots. Lab tests showed no significant difference in hydrophobic behavior of the topsoil and crust material. Micro and macro-structural properties of the topsoil did not differ significantly between the termite sites and the control sites. The texture of the top 5 cm of the soil was also found to be not significantly different. The infiltration results are contradictory to the general literature, which reports increased infiltration rates after prolonged termite activity although mostly under different initial conditions. The number of nest entrances was clearly higher in the termite areas, but apparently did not significantly affect infiltration. The increased soil organic matter contents in the termite affected areas however, are as expected from literature, but did not improve soil aggregation which would be expected given the importance of organic matter in soil aggregation in this type of soils. One of the explanations for the reduced infiltration rates might be that termites bring clay from the finer textured subsoil to the surface to build casts over the organic material on the surface (mainly millet stems). It is speculated that the excavated clay material could be involved in crust formation, only present is in the upper 0.5 cm of the soil crust, which is enough to block pores in the crust surface, hampering infiltration. The topsoil aggregates are slaking under the summer rainfall and the increase in fine textured material, excavated by the termites, could be incorporated into the crust and reduce infiltration. Furthermore this specific effect might also be related to the type of termite involved, as impacts from ecosystem engineers on their environment is highly dependent on the specific species involved.

Impact of Oriented Clay Particles on X-Ray Spectroscopy Analysis

NASA Astrophysics Data System (ADS)

Lim, A. J. M. S.; Syazwani, R. N.; Wijeyesekera, D. C.

2016-07-01

Understanding the engineering properties of the mineralogy and microfabic of clayey soils is very complex and thus very difficult for soil characterization. Micromechanics of soils recognize that the micro structure and mineralogy of clay have a significant influence on its engineering behaviour. To achieve a more reliable quantitative evaluation of clay mineralogy, a proper sample preparation technique for quantitative clay mineral analysis is necessary. This paper presents the quantitative evaluation of elemental analysis and chemical characterization of oriented and random oriented clay particles using X-ray spectroscopy. Three different types of clays namely marine clay, bentonite and kaolin clay were studied. The oriented samples were prepared by placing the dispersed clay in water and left to settle on porous ceramic tiles by applying a relatively weak suction through a vacuum pump. Images form a Scanning Electron Microscope (SEM) was also used to show the comparison between the orientation patterns of both the sample preparation techniques. From the quantitative analysis of the X-ray spectroscopy, oriented sampling method showed more accuracy in identifying mineral deposits, because it produced better peak intensity on the spectrum and more mineral content can be identified compared to randomly oriented samples.

Study of the rheological properties of water and Martian soil simulant mixtures for engineering applications on the red planet

NASA Astrophysics Data System (ADS)

Taylor, Lewis; Alberini, Federico; Sullo, Antonio; Meyer, Marit E.; Alexiadis, Alessio

2018-03-01

The rheological properties of mixtures of water and the Martian soil simulant JSC-Mars-1A are investigated by preparing and testing samples at various solids concentrations. The results indicate that the dispersion is viscoelastic and, at small timescales (∼0.1 s), reacts to sudden strain as an elastic solid. At longer timescales the dispersion behaves like a Bingham fluid and exhibits a yield stress. Hysteresis loops show that rapid step-changes (2 s duration) of shear-rate result in thixotropic behaviour, but slower changes (>10 s duration) can result in rheopexy. These observations are explained with the breakdown and recovery of the packing structure under stress. The rheological information is used to generate practical tools, such as the system curve and the Moody chart that can be used for designing piping systems, and calculating pump sizes and pressure requirements.

Land preparation techniques and vegetation type commonly determine soil conditions in a typical hilly watershed, Loess Plateau of China.

NASA Astrophysics Data System (ADS)

Yu, Yang; Wei, Wei; Chen, Liding; Feng, Tianjiao; Qin, Wei

2017-04-01

Soil is a key component of the earth, it plays important role in regulating the chemical, hydrological and biological cycles. Land preparation techniques (e.g., leveled ditches, leveled benches, adversely graded tableland and fish-scale pits) is one of the most effective ecological engineering practices to reduce water erosion. Land preparation greatly affects soil physicochemical properties, soil moisture variation, runoff and sediment prevention. This study investigated the influence of different land preparation techniques on soil conditions, runoff and erosion during vegetation restoration, which remained poorly understand to date. Soil samples were collected from depths of 0-10 cm, 10-20 cm, 20-40 cm, 40-60 cm, 60-80 cm and 80-100 cm, in the typical hilly watershed of Dingxi City, Loess Plateau. Soil bulk density (BD), soil organic matter (SOM) and total nitrogen (TN) were determined for different land preparations and vegetation type (Caragana korshinskii, Platycladus orientalis, Pinus tabulaeformis and Prunus armeniaca) combinations. Fractal theory was used to analyze the soil particle size distribution (PSD). Redundancy analyses were conducted to distinguish the relationships between soil conditions and the factors influencing them (land preparation and vegetation). The analysis of runoff coefficient and erosion rates were calculated considering the monitoring time. The results indicated that: 1) the effect of land preparation on soil properties and PSD varies with soil depth. For each land preparation category, SOM and TN values showed a significant difference between the top soil layer and the underlying soil depth. 2) The 20 cm soil layer was a boundary that distinguished the explanatory factors, with land preparation and vegetation type as the controlling factors in the 0-20 cm and 20-100 cm soil layers, respectively. Land preparation and vegetation significantly affected soil properties in the surface soil layer, while land preparation (41.6%) was the more important driver for this layer compared with vegetation (37.2%). Land preparation affected the soil properties by abiotic factors (e.g., surface runoff and sediment transport), while vegetation influenced soil physical and chemical properties via biotic factors (e.g., canopy and root). 3) Fish-scale pits-Pinus tabulaeformis had the highest runoff coefficient (3.91%) and adverse grade tableland-Platycladus orientalis had the lowest (1.10%). The runoff coefficient of level bench-Caragana korshinskii, fish-scale pits-Platycladus orientalis, level ditch-Prunus armeniaca and adverse grade tableland-Pinus tabulaeformis were 3.02%, 2.59%, 2.42% and 1.58%, respectively. Level bench-Caragana korshinskii had the highest erosion modulus (0.036 t/ha) and adverse grade tableland-Pinus tabulaeformis showed the lowest (0.006 t/ha). Erosion modulus of fish-scale pits-Platycladus orientalis, level ditch-Prunus armeniaca and adverse grade tableland-Platycladus orientalis were 0.026 t/ha, 0.019 t/ha and 0.015 t/ha, respectively. Compared with control, the runoff coefficient could be reduced 37.7%, 31.9%, 44.3%, 60.5%, 18.2% and 63%, respectively. Erosion modulus could be reduced 77.8%, 62.9%, 82.6%, 84.7%, 53.9% and 76.3%, respectively. Our study demonstrated that land preparation techniques and vegetation type commonly determine soil conditions and that land preparation is a recommended method to improve and rehabilitate degraded ecosystems. Applications of land preparation to vegetation restoration in the fragile ecosystems were an effective way for preventing water loss and soil erosion. Considering site-specific land preparation-plant species combinations could be critical to ensure long-term land stabilization.

Soil engineering in vivo: harnessing natural biogeochemical systems for sustainable, multi-functional engineering solutions

PubMed Central

DeJong, Jason T.; Soga, Kenichi; Banwart, Steven A.; Whalley, W. Richard; Ginn, Timothy R.; Nelson, Douglas C.; Mortensen, Brina M.; Martinez, Brian C.; Barkouki, Tammer

2011-01-01

Carbon sequestration, infrastructure rehabilitation, brownfields clean-up, hazardous waste disposal, water resources protection and global warming—these twenty-first century challenges can neither be solved by the high-energy consumptive practices that hallmark industry today, nor by minor tweaking or optimization of these processes. A more radical, holistic approach is required to develop the sustainable solutions society needs. Most of the above challenges occur within, are supported on, are enabled by or grown from soil. Soil, contrary to conventional civil engineering thought, is a living system host to multiple simultaneous processes. It is proposed herein that ‘soil engineering in vivo’, wherein the natural capacity of soil as a living ecosystem is used to provide multiple solutions simultaneously, may provide new, innovative, sustainable solutions to some of these great challenges of the twenty-first century. This requires a multi-disciplinary perspective that embraces the science of biology, chemistry and physics and applies this knowledge to provide multi-functional civil and environmental engineering designs for the soil environment. For example, can native soil bacterial species moderate the carbonate cycle in soils to simultaneously solidify liquefiable soil, immobilize reactive heavy metals and sequester carbon—effectively providing civil engineering functionality while clarifying the ground water and removing carbon from the atmosphere? Exploration of these ideas has begun in earnest in recent years. This paper explores the potential, challenges and opportunities of this new field, and highlights one biogeochemical function of soil that has shown promise and is developing rapidly as a new technology. The example is used to propose a generalized approach in which the potential of this new field can be fully realized. PMID:20829246

Soil engineering in vivo: harnessing natural biogeochemical systems for sustainable, multi-functional engineering solutions.

PubMed

DeJong, Jason T; Soga, Kenichi; Banwart, Steven A; Whalley, W Richard; Ginn, Timothy R; Nelson, Douglas C; Mortensen, Brina M; Martinez, Brian C; Barkouki, Tammer

2011-01-06

Carbon sequestration, infrastructure rehabilitation, brownfields clean-up, hazardous waste disposal, water resources protection and global warming-these twenty-first century challenges can neither be solved by the high-energy consumptive practices that hallmark industry today, nor by minor tweaking or optimization of these processes. A more radical, holistic approach is required to develop the sustainable solutions society needs. Most of the above challenges occur within, are supported on, are enabled by or grown from soil. Soil, contrary to conventional civil engineering thought, is a living system host to multiple simultaneous processes. It is proposed herein that 'soil engineering in vivo', wherein the natural capacity of soil as a living ecosystem is used to provide multiple solutions simultaneously, may provide new, innovative, sustainable solutions to some of these great challenges of the twenty-first century. This requires a multi-disciplinary perspective that embraces the science of biology, chemistry and physics and applies this knowledge to provide multi-functional civil and environmental engineering designs for the soil environment. For example, can native soil bacterial species moderate the carbonate cycle in soils to simultaneously solidify liquefiable soil, immobilize reactive heavy metals and sequester carbon-effectively providing civil engineering functionality while clarifying the ground water and removing carbon from the atmosphere? Exploration of these ideas has begun in earnest in recent years. This paper explores the potential, challenges and opportunities of this new field, and highlights one biogeochemical function of soil that has shown promise and is developing rapidly as a new technology. The example is used to propose a generalized approach in which the potential of this new field can be fully realized.

An Annotated Bibliography of Patents Related to Coastal Engineering. Volume I. 1967-1970. Appendix.

DTIC Science & Technology

1979-11-01

HYDRAULIC MODEL BASIN PILE, STRUCTURE CONNECTION ICE PROTECTION PILE, WOOD 16 -- mi • . ... -- POLLUTANT ABSORPTION SEISMIC ACOUSTIC TRANSMITTER ARRAY...NT SEABED PIPELINE PLACEMENT WIND MEASUREMENT SEABED PROPERTY MEASUREMENT WOOD PRESERVATIVE SEABED SCOUR PROTECTION SEABED SITE SURVEY SEABED SOIL...concrete, wood , or thin steel piling to aid driving. PILE EXTRACTOR - A means of removing a pile from the earth. PILE FOOTING - A means of increasing a

Feasibility study of a soil-based rubberized CLSM.

PubMed

Wu, Jason Y; Tsai, Mufan

2009-02-01

The development of beneficial uses of recycled scrap tires is always in great demand around the world. The disposal of on-site surplus excavated soil and the production of standard engineering aggregates have also been facing increasing environmental and ecological challenges in congested islands, such as Taiwan. This paper presents an experimental study using recycled crumb rubber and native silty sand to produce a lightweight, soil-based, rubberized controlled low strength material (CLSM) for a bridge approach repair. To assess the technical feasibility of this material, the effects of weight ratios of cement-to-water (C/W) and water-to-solid (W/S), and of rubber content on the engineering properties for different mixtures were investigated. The presented test results include flowability, unit weight, strength, settlement potential, and bearing capacity. Based on the findings, we conclude that a soil-based rubberized CLSM with 40% sand by weight and an optimal design ratio of 0.7 for C/W and 0.35 for W/S can be used for the proposed bridge approach repair. Such a mixture has demonstrated acceptable flowability, strength, and bearing capacity. Its lower unit weight, negligible compressibility, and hydrocollapse potential also help ensure that detrimental settlement is unlikely to occur. The results illustrate a novel scheme of CLSM production, and suggest a beneficial alternative for the reduction of scrap tires as well as conservation of resources and environment.

Soil compaction vulnerability at Organ Pipe Cactus National Monument, Arizona

USGS Publications Warehouse

Webb, Robert H.; Nussear, Kenneth E.; Carmichael, Shinji; Esque, Todd C.

2014-01-01

Compaction vulnerability of different types of soils by hikers and vehicles is poorly known, particularly for soils of arid and semiarid regions. Engineering analyses have long shown that poorly sorted soils (for example, sandy loams) compact to high densities, whereas well-sorted soils (for example, eolian sand) do not compact, and high gravel content may reduce compaction. Organ Pipe Cactus National Monument (ORPI) in southwestern Arizona, is affected greatly by illicit activities associated with the United States–Mexico border, and has many soils that resource managers consider to be highly vulnerable to compaction. Using geospatial soils data for ORPI, compaction vulnerability was estimated qualitatively based on the amount of gravel and the degree of sorting of sand and finer particles. To test this qualitative assessment, soil samples were collected from 48 sites across all soil map units, and undisturbed bulk densities were measured. A scoring system was used to create a vulnerability index for soils on the basis of particle-size sorting, soil properties derived from Proctor compaction analyses, and the field undisturbed bulk densities. The results of the laboratory analyses indicated that the qualitative assessments of soil compaction vulnerability underestimated the area of high vulnerability soils by 73 percent. The results showed that compaction vulnerability of desert soils, such as those at ORPI, can be quantified using laboratory tests and evaluated using geographic information system analyses, providing a management tool that managers potentially could use to inform decisions about activities that reduce this type of soil disruption in protected areas.

Engineered clay-shredded tyre mixtures as barrier materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Al-Tabbaa, A.; Aravinthan, T.

1997-12-31

An engineered clay consisting of kaolin and bentonite was mixed with shredded tyre in various weight percentages and examined for use as a constituent in a landfill liner. The clay-tyre mixtures properties in terms of compaction, unconfined compressive strength, permeability to water and paraffin, leachability, stress-strain behaviour, free swell behaviour and swelling pressure were investigated. The results show that the dry density and strength reduced with the addition of tyre and also with increased tyre content but that good interaction was developed between the clay and tyre. The strain at failure increased showing reinforcing effect of the tyre. The permeabilitymore » to paraffin was considerably reduced compared to that to water due to the presence of the tyre which caused high swelling pressures to develop. The leachability results indicate initial high concentrations leaching out of the soil-tyre mixtures which will be subjected to dilution in the environment. This work adds evidence to the potential advantages of using soil-tyre mixtures as a landfill liner material.« less

SoilBioHedge, harnessing hedgerow soil biodiversity for restoration of arable soil quality and resilience to climatic extremes and land use changes: The impacts of arable to ley conversion on soil hydrological properties

NASA Astrophysics Data System (ADS)

Grayson, Richard; Holden, Joseph; Chapman, Pippa; Hunt, Sarah; Leake, Jonathan

2017-04-01

Modern agricultural practices pose a significant threat to soil security. Continuous conventional cultivation has been observed to deplete soil organic matter, degrade soil structure, reduce water drainage and water holding capacity, increase nitrate leaching, damage the ecosystem engineer earthworm and mycorrhiza populations and increase the susceptibility of soil and crops to the impacts of climatic stress through decreased resilience to flood and drought conditions. The SoilBioHedge project aims to determine the effectiveness of using grass-clover leys linking hedgerows to arable fields in restoring functional biodiversity, soil quality and resilience to drought and excess rainfall in arable farming. Paired 70m long ley strips have been inserted in to 4 fields. Within each field one ley is connected to the margin while in the other a small 1m fallow area and a steel mesh barrier inserted to bedrock is being used to disconnect the ley and margin and prevent macrofaunal movement from the margin to the ley. As part of the SoilBioHedge project we are undertaking a range of analyses to establish the impacts of arable to ley conversion on key hydrological properties of agricultural soils. Soil moisture is being continuously monitored at three depths at 48 separate locations, in addition monthly manual measurements are being taken at 1158 locations. Arable-to-ley conversion is expected to increase soil macrofaunal activity especially in locations closer to hedgerows, enhancing macropore development. Therefore the proportion of water percolating into macropores, mesopores and micropores is being measured using tension infiltrometers which also allow the calculation of saturated hydraulic conductivity. Soil cores have been extracted to examine impacts on bulk and particle density and subsequently porosity, with hydraulic conductivity being measured using a lab permeameter. Here we present the results of these analyses over the first 24 months of the project. This includes the impacts of this arable ley conversion on soil moisture dynamics and functional macroporosity.

Assesment of hydraulics properties of technosoil constructed with waste material using Beerkan infiltration

NASA Astrophysics Data System (ADS)

Yilmaz, Deniz; Peyneau, Pierre-Emmanuel; Beaudet, Laure; Cannavo, Patrice; Sere, Geoffroy

2017-04-01

For the characterization of hydraulics soils functions, in situ infiltration experiments are commonly used. The BEST method based on the infiltration through a single ring is well suited for soils containing coarse material. Technosols built from Civil engineering waste material such as brick waste, concrete waste, track ballast and demolition rubble wastes contain large part of coarse material. In this work, different materials made of civil engineering wastes mixed with organic wastes are tested for greening applications in an urban environment using in situ lysimeters. Beerkan infiltrations experiments were performed on these technosols. Experimental data are used to estimate hydraulics properties through the BEST method. The results shows from a hydraulic point of view that studied technosols can achieve the role of urban soil for greening application. Five combinations of artefacts were tested either as "growing material" (one combination) or "structural material" (4 combinations) - as support for traffic. Structural materials consisted in 27 wt.% earth material, 60 wt.% mineral coarse material and 3 wt.% organic material. These constructed technosols were studied in situ using lysimeters under two contrasted climatic conditions in two sites in France (Angers, in northwestern France and Homécourt, in northeastern France). Constructed technosols exhibited high porosities (31-48 vol% for structural materials, 70 vol% for the growing material). The dry bulk density of the growing material is estimated to 0.66 kg/m3 and 1.59 kg/m3 for structural material. The particle size distribution analysis, involving manual sieving (> 2 mm) and complemented by a grain size analysis (< 2 mm) were used as described in the BEST method (2006) for the estimation of the shape parameter n of hydraulics functions (Van-Genuchten -Mualem, 1980). This n parameter was estimated to 2.23 for growing materials and 2.29 for structural materials. Beerkan infiltrations experiments data were inversed using the BEST method, the results exhibited high saturated hydraulic conductivities 10.7 cm/h for structural materials and 14,8 cm/h for the growing material. Beerkan infiltration experiements are well suited for assesment of hydraulic properties of technosol constructed with civil engineering wastes. According to the estimated hydraulics functions, the studied technosols can be classified between a sand and a loam soil. It shows that these materials can achieve the role of alternative to the consumption of natural arable earth for urban greening applications such as gardens, parks and trees lines.

Effects of nano-SiO2 on the adsorption of chiral metalaxyl to agricultural soils.

PubMed

Huang, Junxing; Liang, Chuanzhou; Zhang, Xu

2017-06-01

The application of nanotechnology in agriculture, pesticide delivery and other related fields increases the occurrence of engineered nanoparticles (ENPs) in soil. Since ENPs have larger surface areas and normally a high adsorption capacity for organic pollutants, they are thought to influence the transport of pesticides in soils and thereafter influence the uptake and transformation of pesticides. The adsorption pattern of racemic-metalaxyl on agricultural soils including kinetics and isotherms changed in the presence of nano-SiO 2 . The adsorption of racemic-metalaxyl on agricultural soil was not enantioselective, in either the presence or the absence of SiO 2 . The adsorption of racemic-metalaxyl on SiO 2 decreased to some extent in soil-SiO 2 mixture, and the absolute decrease was dependent on soil properties. The decreased adsorption of metalaxyl on SiO 2 in soil-SiO 2 mixture arose from the competitive adsorption of soil-dissolved organic matter and the different dispersion and aggregation behaviors of SiO 2 in the presence of soil. Interactions between SiO 2 and soil particles also contributed to the decreased adsorption of metalaxyl on SiO 2 , and the interactions were analyzed by extended Derjaguin-Landau-Verwey-Overbeek theory. The results showed that the presence of nano-particles in soils could decrease the mobility of pesticides in soils and that this effect varied with different soil compositions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Influence of soil properties on the toxicity of TiO₂ nanoparticles on carbon mineralization and bacterial abundance.

PubMed

Simonin, Marie; Guyonnet, Julien P; Martins, Jean M F; Ginot, Morgane; Richaume, Agnès

2015-01-01

Information regarding the impact of low concentration of engineered nanoparticles on soil microbial communities is currently limited and the importance of soil characteristics is often neglected in ecological risk assessment. To evaluate the impact of TiO2 nanoparticles (NPs) on soil microbial communities (measured on bacterial abundance and carbon mineralization activity), 6 agricultural soils exhibiting contrasted textures and organic matter contents were exposed for 90 days to a low environmentally relevant concentration or to an accidental spiking of TiO2-NPs (1 and 500mgkg(-1) dry soil, respectively) in microcosms. In most soils, TiO2-NPs did not impact the activity and abundance of microbial communities, except in the silty-clay soil (high OM) where C-mineralization was significantly lowered, even with the low NPs concentration. Our results suggest that TiO2-NPs toxicity does not depend on soil texture but likely on pH and OM content. We characterized TiO2-NPs aggregation and zeta potential in soil solutions, in order to explain the difference of TiO2-NPs effects on soil C-mineralization. Zeta potential and aggregation of TiO2-NPs in the silty-clay (high OM) soil solution lead to a lower stability of TiO2-NP-aggregates than in the other soils. Further experiments would be necessary to evaluate the relationship between TiO2-NPs stability and toxicity in the soil. Copyright © 2014 Elsevier B.V. All rights reserved.

2D soil and engineering-seismic bedrock modeling of eastern part of Izmir inner bay/Turkey

NASA Astrophysics Data System (ADS)

Pamuk, Eren; Akgün, Mustafa; Özdağ, Özkan Cevdet; Gönenç, Tolga

2017-02-01

Soil-bedrock models are used as a base when the earthquake-soil common behaviour is defined. Moreover, the medium which is defined as bedrock is classified as engineering and seismic bedrock in itself. In these descriptions, S-wave velocity is (Vs) used as a base. The mediums are called soil where the Vs is < 760 m/s, the bigger ones are called bedrock as well. Additionally, the parts are called engineering bedrock where the Vs is between 3000 m/s and 760 m/s, the parts where are bigger than 3000 m/s called seismic bedrock. The interfacial's horizontal topography where is between engineering and seismic bedrock is effective on earthquake's effect changing on the soil surface. That's why, 2D soil-bedrock models must be used to estimate the earthquake effect that could occur on the soil surface. In this research, surface wave methods and microgravity method were used for occuring the 2D soil-bedrock models in the east of İzmir bay. In the first stage, velocity values were obtained by the studies using surface wave methods. Then, density values were calculated from these velocity values by the help of the empiric relations. 2D soil-bedrock models were occurred based upon both Vs and changing of density by using these density values in microgravity model. When evaluating the models, it was determined that the soil is 300-400 m thickness and composed of more than one layers in parts where are especially closer to the bay. Moreover, it was observed that the soil thickness changes in the direction of N-S. In the study area, geologically, it should be thought the engineering bedrock is composed of Bornova melange and seismic bedrock unit is composed of Menderes massif. Also, according to the geophysical results, Neogene limestone and andesite units at between 200 and 400 m depth show that engineering bedrock characteristic.

Study on Calculation Model of Culvert Soil Pressure

NASA Astrophysics Data System (ADS)

Liu, Jing; Tian, Xiao-yan; Gao, Xiao-mei

2017-09-01

Culvert diseases are prevalent in highway engineering. There are many factors involved in the occurrence of the disease, and the problem is complex. However, the design cannot accurately determine the role of the soil pressure on the culvert is the main reason to the disease. Based on the theoretical analysis and field test, this paper studies the characteristics of the stress and deformation of the culvert-soil structure. According to the theory of soil mechanics, the calculation model of vertical soil pressure at the top of culvert is determined, and the formula of vertical soil pressure at the top of culvert is deduced. Through the field test of the vertical soil pressure at the top of culvert of several engineering examples, the calculation formula of this paper is verified, which can provide reference for future practical engineering.

Induced polarization for characterizing and monitoring soil stabilization processes

NASA Astrophysics Data System (ADS)

Saneiyan, S.; Ntarlagiannis, D.; Werkema, D. D., Jr.

2017-12-01

Soil stabilization is critical in addressing engineering problems related to building foundation support, road construction and soil erosion among others. To increase soil strength, the stiffness of the soil is enhanced through injection/precipitation of a chemical agents or minerals. Methods such as cement injection and microbial induced carbonate precipitation (MICP) are commonly applied. Verification of a successful soil stabilization project is often challenging as treatment areas are spatially extensive and invasive sampling is expensive, time consuming and limited to sporadic points at discrete times. The geophysical method, complex conductivity (CC), is sensitive to mineral surface properties, hence a promising method to monitor soil stabilization projects. Previous laboratory work has established the sensitivity of CC on MICP processes. We performed a MICP soil stabilization projects and collected CC data for the duration of the treatment (15 days). Subsurface images show small, but very clear changes, in the area of MICP treatment; the changes observed fully agree with the bio-geochemical monitoring, and previous laboratory experiments. Our results strongly suggest that CC is sensitive to field MICP treatments. Finally, our results show that good quality data alone are not adequate for the correct interpretation of field CC data, at least when the signals are low. Informed data processing routines and the inverse modeling parameters are required to produce optimal results.

Formation of Nanophase Iron in Lunar Soil Simulant for Use in ISRU Studies

NASA Technical Reports Server (NTRS)

Liu, Yang; Taylor, Lawrence A.; Hill, Eddy; Day, James D. M.

2005-01-01

For the prospective return of humans to the Moon and the extensive amount of premonitory studies necessary, large quantities of lunar soil simulants are required, for a myriad of purposes from construction/engineering purposes all the way to medical testing of its effects from ingestion by humans. And there is only a limited and precious quantity of lunar soil available on Earth (i.e., Apollo soils) - therefore, the immediate need for lunar soil simulants. Since the Apollo era, there have been several simulants; of these JSC-1 (Johnson Space Center) and MLS-1 (Minnesota Lunar Simulant) have been the most widely used. JSC-1 was produced from glassy volcanic tuff in order to approximate lunar soil geotechnical properties; whereas, MLS-1 approximates the chemistry of Apollo 11 high-Ti soil, 10084. Stocks of both simulants are depleted, but JSC-1 has recently gone back into production. The lunar soil simulant workshop, held at Marshall Space Flight Center in January 2005, identified the need to make new simulants for the special properties of lunar soil, such as nanophase iron (np-Fe(sup 0). Hill et al. (2005, this volume) showed the important role of microscale Fe(sup 0) in microwave processing of the lunar soil simulants JSC-1 and MLS-1. Lunar soil is formed by space weathering of lunar rocks (e.g., micrometeorite impact, cosmic particle bombardment). Glass generated during micrometeorite impact cements rock and mineral fragments together to form aggregates called agglutinates, and also produces vapor that is deposited and coats soil grains. Taylor et al. (2001) showed that the relative amount of impact glass in lunar soil increases with decreasing grain size and is the most abundant component in lunar dust (less than 20 micrometer fraction). Notably, the magnetic susceptibility of lunar soil also increases with the decreasing grain size, as a function of the amount of nanophase-sized Fe(sup 0) in impact-melt generated glass. Keller et al. (1997, 1999) also discovered the presence of abundant np-Fe(sup 0) particles in the glass patinas coating most soil particles. Therefore, the correlation of glass content and magnetic susceptibility can be explained by the presence of the np-Feo particles in glass: small particles contain relatively more np-Fe(sup 0) as glass coatings because the surface area versus mass ratio of the grain size is so increased. The magnetic properties of lunar soil are important in dust mitigation on the Moon (Taylor et al. 2005). Thus material simulating this property is important for testing mitigation methods using electromagnetic field. This np- Fe(sup 0) also produces a unique energy coupling to normal microwaves, such as present in kitchen microwave ovens. Effectively, a portion of lunar soil placed in a normal 2.45 GHz oven will melt at greater than 1200 C before your tea will boil at 100 C, a startling and new discovery reported by Taylor and Meek (2004, 2005). Several methods have been investigated in attempts to make nanophase-sized Feo dispersed within silicate glass; like in the lunar glass. We have been successful in synthesizing such a product and continue to improve on our recipe. We have performed extensive experimentation on this subject to date. Ultimately it will probably be necessary to add this np-Fe(sup 0) bearing silicate glass to lunar soil stimulant, like JSC-1, to actually produce the desired magnetic and microwave coupling properties for use in appropriate ISRU experimentation.

Functional diversity of soil invertebrates: a potential tool to explain N2O emission?

NASA Astrophysics Data System (ADS)

Lubbers, Ingrid; De Deyn, Gerlinde; Drake, Harold; Hunger, Sindy; Oppermann, Timo; van Groenigen, Jan Willem

2017-04-01

Soil biota play a crucial role in the mineralization of nutrients from organic material. However, they can thereby increase emissions of the potent greenhouse gas nitrous oxide (N2O). Our current lack of understanding of the factors controlling N2O production and emission is impeding the development of effective mitigation strategies. It is the challenge to control N2O emissions from production systems without reducing crop yield, and diversity of soil fauna may play a key role. A high functional diversity of soil invertebrates is known to stimulate nitrogen mineralization and thereby plant growth, however, it is unknown whether a high functional diversity of soil invertebrates can concurrently diminish N2O emissions. We hypothesized that increased functional diversity of soil invertebrates reduces faunal-induced N2O emissions by facilitating more complete denitrification through (i) stimulating the activity of denitrifying microbes, and (ii) affecting the distribution of micro and macro pores, creating more anaerobic reaction sites. Using state-of-the-art X-ray tomography and next-generation sequencing, we studied effects of functional diversity on soil structural properties and the diversity of the microbial community (16S rRNA genes and 16S rRNA), and linked these to soil N2O emissions. In a 120-day study we found that the functional composition of the soil invertebrate community determined N2O emissions: earthworm activity was key to faunal-induced N2O emissions (a 32-fold increase after 120 days, P<0.001). No proof was found to explain faunal-induced N2O emissions through differences in stimulated microbial activity. On the other hand, soil structural properties (mean pore size, pore size distribution) were found to be radically altered by earthworm activity. We conclude that the presence of a few functional groups (ecosystem engineers) is more important than overall increased functional diversity in explaining faunal-affected N2O emissions.

Comparison of Shear Strength Properties for Undisturbed and Reconstituted Parit Nipah Peat, Johor

NASA Astrophysics Data System (ADS)

Azhar, A. T. S.; Norhaliza, W.; Ismail, B.; Abdullah, M. E.; Zakaria, M. N.

2016-11-01

Shear strength of soil is required to determine the soil stability and design the foundations. Peat is known as a soil with complex natural formations which also contributes problems to the researchers, developers, engineers and contractors in constructions and infrastructures. Most researchers conducted experiment and investigation of shear strength on peat using shear box test and simple shear test, but only a few had discovered the behavior of peat using triaxial consolidated undrained test. The aim of this paper is to determine the undrained shear strength properties of reconstituted peat and undisturbed peat of Parit Nipah, Johor for comparison purposes. All the reconstituted peat samples were formed with the size that passed opening sieve 3.35 mm and preconsolidation pressure at 100 kPa. The result of undrained shear strength of reconstituted peat was 21kPa for cohesion with the angle of friction, 41° compare to the undisturbed peat with cohesion 10 kPa and angle of friction, 16°. The undrained shear strength properties result obtained shows that the reconstituted peat has higher strength than undisturbed peat. For relationship deviator stress-strain, σd max and excess pore pressure, Δu, it shows that both of undisturbed and reconstituted gradually increased when σ’ increased, but at the end of the test, the values are slightly dropped. The physical properties of undisturbed and reconstituted peat were also investigated to correlate with the undrained shear strength results.

A review of the impacts of degradation threats on soil properties in the UK.

PubMed

Gregory, A S; Ritz, K; McGrath, S P; Quinton, J N; Goulding, K W T; Jones, R J A; Harris, J A; Bol, R; Wallace, P; Pilgrim, E S; Whitmore, A P

2015-10-01

National governments are becoming increasingly aware of the importance of their soil resources and are shaping strategies accordingly. Implicit in any such strategy is that degradation threats and their potential effect on important soil properties and functions are defined and understood. In this paper, we aimed to review the principal degradation threats on important soil properties in the UK, seeking quantitative data where possible. Soil erosion results in the removal of important topsoil and, with it, nutrients, C and porosity. A decline in soil organic matter principally affects soil biological and microbiological properties, but also impacts on soil physical properties because of the link with soil structure. Soil contamination affects soil chemical properties, affecting nutrient availability and degrading microbial properties, whilst soil compaction degrades the soil pore network. Soil sealing removes the link between the soil and most of the 'spheres', significantly affecting hydrological and microbial functions, and soils on re-developed brownfield sites are typically degraded in most soil properties. Having synthesized the literature on the impact on soil properties, we discuss potential subsequent impacts on the important soil functions, including food and fibre production, storage of water and C, support for biodiversity, and protection of cultural and archaeological heritage. Looking forward, we suggest a twin approach of field-based monitoring supported by controlled laboratory experimentation to improve our mechanistic understanding of soils. This would enable us to better predict future impacts of degradation processes, including climate change, on soil properties and functions so that we may manage soil resources sustainably.

DECOMPOSTION OF GENETICALLY ENGINEERED TOBACCO UNDER FIELD CONDITIONS: PERSISTENCE OF THE PROTEINASE INHIBITOR I PRODUCT AND EFFECTS OF SOIL MICROBIAL RESPIRATION AND PROTOZOA, NEMATODE AND MICROARTHR

EPA Science Inventory

1. To evaluate the potential effects of genetically engineered (transgenic) plants on soil ecosystems, litterbags containing leaves of non-engineered (parental) and transgenic tobacco plants were buried in field plots. The transgenic tobacco plants were genetically engineered to ...

Ground-penetrating radar research in Belgium: from developments to applications

NASA Astrophysics Data System (ADS)

Lambot, Sébastien; Van Meirvenne, Marc; Craeye, Christophe

2014-05-01

Ground-penetrating radar research in Belgium spans a series of developments and applications, including mainly ultra wideband radar antenna design and optimization, non-destructive testing for the characterization of the electrical properties of soils and materials, and high-resolution subsurface imaging in agricultural engineering, archeology and transport infrastructures (e.g., road inspection and pipe detection). Security applications have also been the topic of active research for several years (i.e., landmine detection) and developments in forestry have recently been initiated (i.e., for root zone and tree trunk imaging and characterization). In particular, longstanding research has been devoted to the intrinsic modeling of antenna-medium systems for full-wave inversion, thereby providing an effective way for retrieving the electrical properties of soils and materials. Full-wave modeling is a prerequisite for benefiting from the full information contained in the radar data and is necessary to provide robust and accurate estimates of the properties of interest. Nevertheless, this has remained a major challenge in geophysics and electromagnetics for many years, mainly due to the complex interactions between the antennas and the media as well as to the significant computing resources that are usually required. Efforts have also been dedicated to the development of specific inversion strategies to cope with the complexity of the inverse problems usually dealt with as well as ill-posedness issues that arise from a lack of information in the radar data. To circumvent this last limitation, antenna arrays have been developed and modeled in order to provide additional information. Moreover, data fusion ways have been investigated, by mainly combining GPR data with electromagnetic induction complementary information in joint interpretation analyses and inversion procedures. Finally, inversions have been regularized by combining electromagnetics models together with soil hydrodynamic models in mechanistic data assimilation frameworks, assuming process knowledge as information as well. Acknowledgement: GPR research in Belgium benefits from networking activities carried out within the EU funded COST Action TU1208 "Civil Engineering Applications of Ground Penetrating Radar".

Soil moisture and properties estimation by assimilating soil temperatures using particle batch smoother: A new perspective for DTS

NASA Astrophysics Data System (ADS)

Dong, J.; Steele-Dunne, S. C.; Ochsner, T. E.; Van De Giesen, N.

2015-12-01

Soil moisture, hydraulic and thermal properties are critical for understanding the soil surface energy balance and hydrological processes. Here, we will discuss the potential of using soil temperature observations from Distributed Temperature Sensing (DTS) to investigate the spatial variability of soil moisture and soil properties. With DTS soil temperature can be measured with high resolution (spatial <1m, and temporal < 1min) in cables up to kilometers in length. Soil temperature evolution is primarily controlled by the soil thermal properties, and the energy balance at the soil surface. Hence, soil moisture, which affects both soil thermal properties and the energy that participates the evaporation process, is strongly correlated to the soil temperatures. In addition, the dynamics of the soil moisture is determined by the soil hydraulic properties.Here we will demonstrate that soil moisture, hydraulic and thermal properties can be estimated by assimilating observed soil temperature at shallow depths using the Particle Batch Smoother (PBS). The PBS can be considered as an extension of the particle filter, which allows us to infer soil moisture and soil properties using the dynamics of soil temperature within a batch window. Both synthetic and real field data will be used to demonstrate the robustness of this approach. We will show that the proposed method is shown to be able to handle different sources of uncertainties, which may provide a new view of using DTS observations to estimate sub-meter resolution soil moisture and properties for remote sensing product validation.

Shear-wave velocity-based probabilistic and deterministic assessment of seismic soil liquefaction potential

USGS Publications Warehouse

Kayen, R.; Moss, R.E.S.; Thompson, E.M.; Seed, R.B.; Cetin, K.O.; Der Kiureghian, A.; Tanaka, Y.; Tokimatsu, K.

2013-01-01

Shear-wave velocity (Vs) offers a means to determine the seismic resistance of soil to liquefaction by a fundamental soil property. This paper presents the results of an 11-year international project to gather new Vs site data and develop probabilistic correlations for seismic soil liquefaction occurrence. Toward that objective, shear-wave velocity test sites were identified, and measurements made for 301 new liquefaction field case histories in China, Japan, Taiwan, Greece, and the United States over a decade. The majority of these new case histories reoccupy those previously investigated by penetration testing. These new data are combined with previously published case histories to build a global catalog of 422 case histories of Vs liquefaction performance. Bayesian regression and structural reliability methods facilitate a probabilistic treatment of the Vs catalog for performance-based engineering applications. Where possible, uncertainties of the variables comprising both the seismic demand and the soil capacity were estimated and included in the analysis, resulting in greatly reduced overall model uncertainty relative to previous studies. The presented data set and probabilistic analysis also help resolve the ancillary issues of adjustment for soil fines content and magnitude scaling factors.

Geotechnical engineering in US elementary schools

NASA Astrophysics Data System (ADS)

Suescun-Florez, Eduardo; Iskander, Magued; Kapila, Vikram; Cain, Ryan

2013-06-01

This paper reports on the results of several geotechnical engineering-related science activities conducted with elementary-school students. Activities presented include soil permeability, contact stress, soil stratigraphy, shallow and deep foundations, and erosion in rivers. The permeability activity employed the LEGO NXT platform for data acquisition, the soil profile and foundations activity employed natural and transparent soils as well as LEGO-based foundation models, and the erosion activity utilised a 3D printer to assist with construction of building models. The activities seek to enhance students' academic achievement, excite them about geotechnical engineering, and motivate them to study science and math. Pre- and post-activity evaluations were conducted to assess both the suitability of the activities and the students' learning. Initial results show that students gain a reasonable understanding of engineering principles. Moreover, the geotechnical engineering activities provided students an opportunity to apply their math skills and science knowledge.

Nanoscale Interactions between Engineered Nanomaterials and Black Carbon (Biochar) in Soil

USDA-ARS?s Scientific Manuscript database

An understanding of the interactions between engineered nanomaterials (NMs) and soil constituents, and a comprehension of how these interactions may affect biological uptake and toxicity are currently lacking. Charcoal black carbon is a normal constituent of soils due to fire history, and can be pre...

QA/QC requirements for physical properties sampling and analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Innis, B.E.

1993-07-21

This report presents results of an assessment of the available information concerning US Environmental Protection Agency (EPA) quality assurance/quality control (QA/QC) requirements and guidance applicable to sampling, handling, and analyzing physical parameter samples at Comprehensive Environmental Restoration, Compensation, and Liability Act (CERCLA) investigation sites. Geotechnical testing laboratories measure the following physical properties of soil and sediment samples collected during CERCLA remedial investigations (RI) at the Hanford Site: moisture content, grain size by sieve, grain size by hydrometer, specific gravity, bulk density/porosity, saturated hydraulic conductivity, moisture retention, unsaturated hydraulic conductivity, and permeability of rocks by flowing air. Geotechnical testing laboratories alsomore » measure the following chemical parameters of soil and sediment samples collected during Hanford Site CERCLA RI: calcium carbonate and saturated column leach testing. Physical parameter data are used for (1) characterization of vadose and saturated zone geology and hydrogeology, (2) selection of monitoring well screen sizes, (3) to support modeling and analysis of the vadose and saturated zones, and (4) for engineering design. The objectives of this report are to determine the QA/QC levels accepted in the EPA Region 10 for the sampling, handling, and analysis of soil samples for physical parameters during CERCLA RI.« less

Rock Content Influence on Soil Hydraulic Properties

NASA Astrophysics Data System (ADS)

Parajuli, K.; Sadeghi, M.; Jones, S. B.

2015-12-01

Soil hydraulic properties including the soil water retention curve (SWRC) and hydraulic conductivity function are important characteristics of soil affecting a variety of soil properties and processes. The hydraulic properties are commonly measured for seived soils (i.e. particles < 2 mm), but many natural soils include rock fragments of varying size that alter bulk hydraulic properties. Relatively few studies have addressed this important problem using physically-based concepts. Motivated by this knowledge gap, we set out to describe soil hydraulic properties using binary mixtures (i.e. rock fragment inclusions in a soil matrix) based on individual properties of the rock and soil. As a first step of this study, special attention was devoted to the SWRC, where the impact of rock content on the SWRC was quantified using laboratory experiments for six different mixing ratios of soil matrix and rock. The SWRC for each mixture was obtained from water mass and water potential measurements. The resulting data for the studied mixtures yielded a family of SWRC indicating how the SWRC of the mixture is related to that of the individual media, i.e., soil and rock. A consistent model was also developed to describe the hydraulic properties of the mixture as a function of the individual properties of the rock and soil matrix. Key words: Soil hydraulic properties, rock content, binary mixture, experimental data.

Where can cone penetrometer technology be applied? Development of a map of Europe regarding the soil penetrability.

PubMed

Fleischer, Matthias; van Ree, Derk; Leven, Carsten

2014-01-01

Over the past decades, significant efforts have been invested in the development of push-in technology for site characterization and monitoring for geotechnical and environmental purposes and have especially been undertaken in the Netherlands and Germany. These technologies provide the opportunity for faster, cheaper, and collection of more reliable subsurface data. However, to maximize the technology both from a development and implementation point of view, it is necessary to have an overview of the areas suitable for the application of this type of technology. Such an overview is missing and cannot simply be read from existing maps and material. This paper describes the development of a map showing the feasibility or applicability of Direct Push/Cone Penetrometer Technology (DPT/CPT) in Europe which depends on the subsurface and its extremely varying properties throughout Europe. Subsurface penetrability is dependent on a range of factors that have not been mapped directly or can easily be inferred from existing databases, especially the maximum depth reachable would be of interest. Among others, it mainly depends on the geology, the soil mechanical properties, the type of equipment used as well as soil-forming processes. This study starts by looking at different geological databases available at the European scale. Next, a scheme has been developed linking geological properties mapped to geotechnical properties to determine basic penetrability categories. From this, a map of soil penetrability is developed and presented. Validating the output by performing field tests was beyond the scope of this study, but for the country of the Netherlands, this map has been compared against a database containing actual cone penetrometer depth data to look for possible contradictory results that would negate the approach. The map for the largest part of Europe clearly shows that there is a much wider potential for the application of Direct Push Technology than is currently seen. The study also shows that there is a lack of large-scale databases that contain depth-resolved data as well as soil mechanical and physical properties that can be used for engineering purposes in relation to the subsurface.

Infiltration performance of engineered surfaces commonly used for distributed stormwater management

NASA Astrophysics Data System (ADS)

Valinski, Nicholas A.

Engineered porous media are commonly used in low impact development (LID) structures to mitigate excess stormwater in urban environments. Differences in infiltrability of these LID systems arise from the wide variety of materials used to create porous surfaces and subsequent maintenance, debris loading, and physical damage. In this study, infiltration capacity of six common materials was tested by multiple replicate experiments with automated mini-disk infiltrometers. The tested materials included porous asphalt, porous concrete, porous brick pavers, flexible porous pavement, engineered soils, and native soils. Porous asphalt, large porous brick pavers, and curb cutout rain gardens showed the greatest infiltration rates. Most engineered porous pavements and soils performed better than the native silt loam soils. Infiltration performance was found to be related more to site design and environmental factors than material choice. Sediment trap zones in both pavements and engineered soil rain gardens were found to be beneficial to the whole site performance. Winter chloride application had a large negative impact on poured in place concrete, making it a poor choice for heavily salted areas.

Infiltration performance of engineered surfaces commonly used for distributed stormwater management.

PubMed

Valinski, N A; Chandler, D G

2015-09-01

Engineered porous media are commonly used in low impact development (LID) structures to mitigate excess stormwater in urban environments. Differences in infiltrability of these LID systems arise from the wide variety of materials used to create porous surfaces and subsequent maintenance, debris loading, and physical damage. In this study, the infiltration capacity of six common materials was tested by multiple replicate experiments with automated mini-disk infiltrometers. The tested materials included porous asphalt, porous concrete, porous brick pavers, flexible porous pavement, engineered soils, and native soils. Porous asphalt, large porous brick pavers, and curb cutout rain gardens showed the greatest infiltration rates. Most engineered porous pavements and soils performed better than the native silt loam soils. Infiltration performance was found to be related more to site design and environmental factors than material choice. Sediment trap zones in both pavements and engineered soil rain gardens were found to be beneficial to the whole site performance. Winter chloride application had a large negative impact on poured in place concrete, making it a poor choice for heavily salted areas. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effects of long-term soil and crop management on soil hydraulic properties for claypan soils

USDA-ARS?s Scientific Manuscript database

Regional and national soil maps have been developed along with associated soil property databases to assist users in making land management decisions based on soil characteristics. These soil properties include average values from soil characterization for each soil series. In reality, these propert...

Physico-chemo-mechanical coupling mechanisms in soil behavior

NASA Astrophysics Data System (ADS)

Hu, Liangbo

Many processes in geomechanics or geotechnical/geomechanical system engineering involve phenomena that are physical and/or chemical in nature, the understanding of which is crucial to modeling the mechanical responses of soils to various loads. Such physico-chemo-mechanical coupling mechanisms are prevalent in two different types of geomechanical processes studied in this dissertation: long-term soil/sediments compaction & desiccation cracking. Most commonly the underlying physical and chemical phenomena are explained, formulated and quantified at microscopic level. In addition to the necessity of capturing the coupling mechanisms, another common thread that emerges in formulating their respective mathematical model is the necessity of linking phenomena occurring at different scales with a theory to be formulated at a macroscopic continuum level. Part I of this dissertation is focused on the subject of long-term compaction behavior of soils and sediments. The interest in this subject arises from the need to evaluate reservoir compaction and land subsidence that may result from oil/gas extraction in petroleum engineering. First, a damage-enhanced reactive chemo-plasticity model is developed to simulate creep of saturated geomaterials, a long-term strain developed at constant stress. Both open and closed systems are studied. The deformation at a constant load in a closed system exhibits most of the characteristics of the classical creep. Primary, secondary and tertiary creep can be interpreted in terms of dominant mechanisms in each phase, emphasizing the role of the rates of dissolution and precipitation, variable reaction areas and chemical softening intensity. The rest of Part I is devoted to the study of soil aging, an effect of a localized mineral dissolution related creep strain and subsequent material stiffening. A three-scale mathematical model is developed to numerically simulate the scenarios proposed based on macroscopic experiments and geochemical evidence. These scale are: micro-scale for intra-grain dissolution, meso-scale for processes within grain assembly and macro-scale of a granular continuum. This model makes it possible to predict the porosity evolution starting from a very simple grain assembly under different pressures at the rneso-scale and evaluate the evolution of the stiffness as a function of the aging duration and the associated stress at the macro-scale. The results are qualitative but reproduce well the main phenomena and tendencies. Subsequently, this model is further examined to study the feedback mechanisms in multi-scale phenomena of sediment compaction and their role in chemo-hydro-geomechanical modeling. Part II of this dissertation deals with desiccation cracking of soils. Presence of cracks is a major cause for the deteriorated and compromised engineering properties of soils in earth works, such as dramatical increase in permeability or decrease of strength. Desiccation cracking is first addressed in an experimental study of shrinkage and cracking of a soil slab with water removed by isothermal drying. This study is followed by a numerical simulation of a solid phase continuum based on hygro-elastic theory. The experiments confirm that a substantial part of shrinkage occurs in the saturated phase and the kinematic boundary constraints play the crucial role in generating tensile stress and eventually cracks. Subsequently a novel experimental parametric study is performed using different liquids for the pore fluids in our experiment to further investigate the role of solid-fluid-gas interaction. Biot's theory is employed to perform a numerical parametric study. The amount of shrinkage depends mainly on the soil compressibility, on the other hand, the rate of fluid removal and rate of shrinkage are found to be controlled by evaporative and permeability properties. Additionally, microscopic experimental and phenomenological study is also performed to link the engineering properties and macroscopic variables to the phenomena occurring at the pore scale. Mercury Intrusion Porosimetry (MIP) technique is used to reveal the evolution of the pore sizes. The large pores are found to be mainly responsible for the shrinking deformation. A microscopic model is developed to simulate the possible scenarios during the entire desaturated phase. A possible quantitative comparison with MIP results and macroscopic experiments is made with using the averaging method to upscale the variables obtained at the micro-scale. The main characteristics of shrinkage behavior observed in macroscopic experiments are generally reproduced.

Martian (and Cold Region Lunar) Soil Mechanics Considerations

NASA Astrophysics Data System (ADS)

Chua, Koon Meng; Johnson, Stewart W.

1998-01-01

The exploration of Mars has generated a lot of interest in recent years. With the completion of the Pathfinder Mission and the commencement of detailed mapping by Mars Global Surveyor, the possibility of an inhabited outpost on the planet is becoming more realistic. In spite of the upbeat mood, human exploration of Mars is still many years in the future. Additionally, the earliest return of any martian soil samples will probably not be until 2008. So why the discussion about martian soil mechanics when there are no returned soil samples on hand to examine? In view of the lack of samples, the basis of this or any discussion at this time must necessarily be one that involves conjecture, but not without the advantage of our knowledge of regolith mechanics of the Moon and soil mechanics on Earth. The objective of this presentation/discussion is fourfold: (1) Review some basic engineering-related information about Mars that may be of interest to engineers, and scientists - including characteristics of water and C02 at low temperature; (2) review and bring together principles of soil mechanics pertinent to studying and predicting how martian soil may behave, including the morphology and physical characteristics of coarse-grained and fine-grained soils (including clays), the characteristics of collapsing soils, potentials and factors that affect migration of water in unfrozen and freezing/frozen soils, and the strength and stiffness characteristics of soils at cold temperatures; (3) discuss some preliminary results of engineering experiments performed with frozen lunar soil simulants, JSC-1, in the laboratory that show the response to temperature change with and without water, effects of water on the strength and stiffness at ambient and at below freezing temperatures; and (4) discuss engineering studies that could be performed prior to human exploration and engineering research to be performed alongside future scientific missions to that planet.

Assessment the effect of homogenized soil on soil hydraulic properties and soil water transport

NASA Astrophysics Data System (ADS)

Mohawesh, O.; Janssen, M.; Maaitah, O.; Lennartz, B.

2017-09-01

Soil hydraulic properties play a crucial role in simulating water flow and contaminant transport. Soil hydraulic properties are commonly measured using homogenized soil samples. However, soil structure has a significant effect on the soil ability to retain and to conduct water, particularly in aggregated soils. In order to determine the effect of soil homogenization on soil hydraulic properties and soil water transport, undisturbed soil samples were carefully collected. Five different soil structures were identified: Angular-blocky, Crumble, Angular-blocky (different soil texture), Granular, and subangular-blocky. The soil hydraulic properties were determined for undisturbed and homogenized soil samples for each soil structure. The soil hydraulic properties were used to model soil water transport using HYDRUS-1D.The homogenized soil samples showed a significant increase in wide pores (wCP) and a decrease in narrow pores (nCP). The wCP increased by 95.6, 141.2, 391.6, 3.9, 261.3%, and nCP decreased by 69.5, 10.5, 33.8, 72.7, and 39.3% for homogenized soil samples compared to undisturbed soil samples. The soil water retention curves exhibited a significant decrease in water holding capacity for homogenized soil samples compared with the undisturbed soil samples. The homogenized soil samples showed also a decrease in soil hydraulic conductivity. The simulated results showed that water movement and distribution were affected by soil homogenizing. Moreover, soil homogenizing affected soil hydraulic properties and soil water transport. However, field studies are being needed to find the effect of these differences on water, chemical, and pollutant transport under several scenarios.

Revised Rapid Soils Analysis Kit (RSAK) - Wet Methodology

DTIC Science & Technology

2018-01-01

respective owners. The findings of this report are not to be construed as an official Department of the Army position unless so designated by other...Airfields and Pavements Branch (GMA) of the Engineering Systems and Materials Division (GM), U.S. Army Engineer Research and Development Center...the soil type and the in-place soil conditions. This research project was designed to provide soldiers who have minimal to no experience in soil

Military Curriculum Materials for Vocational and Technical Education. Soils Engineering 3-1. Edition 1.

ERIC Educational Resources Information Center

Ohio State Univ., Columbus. National Center for Research in Vocational Education.

This individualized, self-paced course for independent study in soils engineering was adapted from military curriculum materials for use in vocational education. The course is designed to acquaint students with various soil types and their characteristics using various procedures, tests, and recording forms. Some of these duties are determining…

ELF Communications System Ecological Monitoring Program: Electromagnetic Field Measurements and Engineering Support-1991

DTIC Science & Technology

1992-12-01

engineering support for completed studies--namely, the wetlands, slime mold , and bird species and communities studies performed in Wisconsin-appears in previous...3 4. ENGINEERING SUPPORT ACTIVITIES 4.1 Soil Amoeba Growth Chambers 4.1.1 Background 3 The soil amoeba and now-completed slime mold studies both...cultures of soil amoeba and slime mold to the earth’s ambient temperature. It is also desirable to expose the cultures to the same EM environment that they

Effects of Carpobrotus edulis invasion on soil gross N fluxes in rocky coastal habitats.

PubMed

Vieites-Blanco, Cristina; González-Prieto, Serafín J

2018-04-01

The effects of alien plants on whole nutrient cycles have been scarcely studied, despite the increasing evidence on their impact on nutrient pools and fluxes. Carpobrotus edulis, a dangerous invasive plant in coastal areas worldwide, is considered an ecosystems engineer which, by changing many soil properties, benefits its own invasion and hampers the restoration of the invaded habitats. To study, for the first time, the 'true' impact of C. edulis on the soil N cycle, we used a paired 15 N labelling experiment and a Ntrace compartment model to estimate the gross N fluxes in the 0-5cm and 5-10cm soil layers of non-invaded and C. edulis invaded areas of two temperate-humid coastal rocky locations. Carpobrotus edulis invasion generally increased NH 4 + immobilization (I NH4 , 1.19-4.48×), presumably due to a lower N availability for the microbiota. The invasion also decreased autotrophic nitrification (O NH4, 0.20-0.79×), either by a direct effect over soil microbiota or by the acidification triggered by C. edulis. Unexpectedly, the dissimilatory nitrate reduction (D NRA ) was the exclusive NO 3 - consuming process modelled on most of the studied soils, although the incubation was aerobic. Apparently, the high organic C content of these soils induced a higher O 2 consumption and the formation of anaerobic microsites where the D NRA could have taken place. The lower NO 3 - availability of invaded soils could explain their lower D NRA rates (0.04-0.70×) compared to native soils. Both D NRA and O NH4 were more affected in the 0-5cm layer, but the invasion also significantly affected N rates in the 5-10cm layer. Overall, net nitrification and mineralization generally decreased in the invaded soils. This study shows that the invasion of C. edulis alters soil gross and net N fluxes in a 0-10cm depth through its effects on soil properties and microbiota. Copyright © 2017 Elsevier B.V. All rights reserved.

Effects of Long-term Soil and Crop Management on Soil Hydraulic Properties for Claypan Soils

USDA-ARS?s Scientific Manuscript database

Regional and national soil maps and associated databases of soil properties have been developed to help land managers make decisions based on soil characteristics. Hydrologic modelers also utilize soil hydraulic properties provided in these databases, in which soil characterization is based on avera...

Root tensile strength of grey alder and mountain maple grown on a coarse grained eco-engineered slope in the Swiss Alps related to wood anatomical features

NASA Astrophysics Data System (ADS)

Kink, Dimitri; Bast, Alexander; Meyer, Christine; Meier, Wolfgang; Egli, Markus; Gärtner, Holger

2014-05-01

Steep, vegetation free slopes are a common feature in alpine areas. The material covering these slopes is prone to all kind of erosional processes, resulting in a high risk potential for population and infrastructure. This risk potential is likely to increase with the predicted change in the spatiotemporal distribution of precipitation events. A potential increase in extreme precipitation events will also result in a higher magnitude and frequency of erosional processes. In the Swiss Alps as in many other mountainous areas, there is a need to stabilize these slopes to reduce their direct or indirect hazard potential. In this regard, eco-engineering is a very promising and sustainable approach for slope stabilization. Planting trees and shrubs is a central task in eco-engineering. A developing vegetation cover will on one hand reduce the mechanical effects of rainfall by an increased interception, on the other hand, the root systems cause modifications of soil properties. Roots not only provide anchorage for the plants, they also promote soil aggregation and are able to penetrate possible shear horizons. Overall, anchorage of plants is at the same extend also stabilizing the near subsurface. When rainfall occurs, the saturated soil exerts downhill pressure to a tree or shrub. As long as the root distribution supports anchorage, the respective slope area remains stable. At this point, the tensile strength of the roots is a critical measure, because it is more likely that the supporting roots break than the entire root system being pulled out of the soil completely. As a consequence, root tensile strength is an important parameter in characterizing the soil stabilization potential of trees and shrubs. It is known that tree roots show a high variability in their anatomical structure depending on their depth below soil surface as well as their distance to the main stem. Therefore, we assume that these structural changes affect the tensile strength of every single root. In order to confirm this assumption and possibly find more important root properties which have an influence on soil stabilization, the root systems of seven trees (three grey alder, four mountain maple) were excavated and analyzed. The study site is a catchment, where shallow landslides are common. It is located in the Prättigau valley in the Eastern Swiss Alps and was eco-engineered in 1997. The substrate is coarse-grained morainic material, mean annual air temperature reaches 4.64°C, average precipitation is 1170 mm, and the altitude is about 1000 m a.s.l.. The root system of each tree was uncovered carefully by hand to keep the roots undamaged, before removal it was photographed in situ to document the root distribution. The root systems were then cut into single root pieces of about 20 cm length and the position of each sample was documented. The root samples were then hierarchically classified in several root classes. The tensile strength of more than 500 samples was determined. In addition, the values for age, diameter, and root moisture were ascertained. Since it was assumed, that the cellular structure of the roots has an influence on the tensile strength, two microscopic thin-sections were prepared from all successfully tested root samples. The microscopic analysis focused on anatomical parameters such as the size and number of vessels, their distribution as well as their conductivity. The results for the final correlation between the anatomical characteristics and the root's tensile strength are presented for both tree species.

Biochemical characteristics of a free cyanide and total nitrogen assimilating Fusarium oxysporum EKT01/02 isolate from cyanide contaminated soil.

PubMed

Akinpelu, Enoch A; Adetunji, Adewole T; Ntwampe, Seteno K O; Nchu, Felix; Mekuto, Lukhanyo

2017-10-01

Sustainability of nutrient requirements for microbial proliferation on a large scale is a challenge in bioremediation processes. This article presents data on biochemical properties of a free cyanide resistant and total nitrogen assimilating fungal isolate from the rhizosphere of Zea mays (maize) growing in soil contaminated with a cyanide-based pesticide. DNA extracted from this isolate were PCR amplified using universal primers; TEF1-α and ITS. The raw sequence files are available on the NCBI database. Characterisation using biochemical data was obtained using colorimetric reagents analysed with VITEK ® 2 software version 7.01. The data will be informative in selection of biocatalyst for environmental engineering application.

The status of soil mapping for the Idaho National Engineering Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Olson, G.L.; Lee, R.D.; Jeppesen, D.J.

This report discusses the production of a revised version of the general soil map of the 2304-km{sup 2} (890-mi{sup 2}) Idaho National Engineering Laboratory (INEL) site in southeastern Idaho and the production of a geographic information system (GIS) soil map and supporting database. The revised general soil map replaces an INEL soil map produced in 1978 and incorporates the most current information on INEL soils. The general soil map delineates large soil associations based on National Resources Conservation Services [formerly the Soil Conservation Service (SCS)] principles of soil mapping. The GIS map incorporates detailed information that could not be presentedmore » on the general soil map and is linked to a database that contains the soil map unit descriptions, surficial geology codes, and other pertinent information.« less

An Underground Revolution: Biodiversity and Soil Ecological Engineering for Agricultural Sustainability.

PubMed

Bender, S Franz; Wagg, Cameron; van der Heijden, Marcel G A

2016-06-01

Soil organisms are an integral component of ecosystems, but their activities receive little recognition in agricultural management strategies. Here we synthesize the potential of soil organisms to enhance ecosystem service delivery and demonstrate that soil biodiversity promotes multiple ecosystem functions simultaneously (i.e., ecosystem multifunctionality). We apply the concept of ecological intensification to soils and we develop strategies for targeted exploitation of soil biological traits. We compile promising approaches to enhance agricultural sustainability through the promotion of soil biodiversity and targeted management of soil community composition. We present soil ecological engineering as a concept to generate human land-use systems, which can serve immediate human needs while minimizing environmental impacts. Copyright © 2016 Elsevier Ltd. All rights reserved.

SMAP Instrument Mechanical System Engineering

NASA Technical Reports Server (NTRS)

Slimko, Eric; French, Richard; Riggs, Benjamin

2013-01-01

The Soil Moisture Active Passive (SMAP) mission, scheduled for launch by the end of 2014, is being developed to measure the soil moisture and soil freeze/thaw state on a global scale over a three-year period. The accuracy, resolution, and global coverage of SMAP measurements are invaluable across many science and applications disciplines including hydrology, climate, carbon cycle, and the meteorological, environment, and ecology applications communities. The SMAP observatory is composed of a despun bus and a spinning instrument platform that includes both a deployable 6 meter aperture low structural frequency Astromesh reflector and a spin control system. The instrument section has engendered challenging mechanical system issues associated with the antenna deployment, flexible antenna pointing in the context of a multitude of disturbances, spun section mass properties, spin control system development, and overall integration with the flight system on both mechanical and control system levels. Moreover, the multitude of organizations involved, including two major vendors providing the spin subsystem and reflector boom assembly plus the flight system mechanical and guidance, navigation, and control teams, has led to several unique system engineering challenges. Capturing the key physics associated with the function of the flight system has been challenging due to the many different domains that are applicable. Key interfaces and operational concepts have led to complex negotiations because of the large number of organizations that integrate with the instrument mechanical system. Additionally, the verification and validation concerns associated with the mechanical system have had required far-reaching involvement from both the flight system and other subsystems. The SMAP instrument mechanical systems engineering issues and their solutions are described in this paper.

Land degradation assessment by geo-spatially modeling different soil erodibility equations in a semi-arid catchment.

PubMed

Saygın, Selen Deviren; Basaran, Mustafa; Ozcan, Ali Ugur; Dolarslan, Melda; Timur, Ozgur Burhan; Yilman, F Ebru; Erpul, Gunay

2011-09-01

Land degradation by soil erosion is one of the most serious problems and environmental issues in many ecosystems of arid and semi-arid regions. Especially, the disturbed areas have greater soil detachability and transportability capacity. Evaluation of land degradation in terms of soil erodibility, by using geostatistical modeling, is vital to protect and reclaim susceptible areas. Soil erodibility, described as the ability of soils to resist erosion, can be measured either directly under natural or simulated rainfall conditions, or indirectly estimated by empirical regression models. This study compares three empirical equations used to determine the soil erodibility factor of revised universal soil loss equation prediction technology based on their geospatial performances in the semi-arid catchment of the Saraykoy II Irrigation Dam located in Cankiri, Turkey. A total of 311 geo-referenced soil samples were collected with irregular intervals from the top soil layer (0-10 cm). Geostatistical analysis was performed with the point values of each equation to determine its spatial pattern. Results showed that equations that used soil organic matter in combination with the soil particle size better agreed with the variations in land use and topography of the catchment than the one using only the particle size distribution. It is recommended that the equations which dynamically integrate soil intrinsic properties with land use, topography, and its influences on the local microclimates, could be successfully used to geospatially determine sites highly susceptible to water erosion, and therefore, to select the agricultural and bio-engineering control measures needed.

Effect of Soil Washing for Lead and Zinc Removal on Soil Hydraulic Properties

NASA Astrophysics Data System (ADS)

Kammerer, Gerhard; Zupanc, Vesna; Gluhar, Simon; Lestan, Domen

2017-04-01

Soil washing as a metal pollution remediation process, especially part with intensive mixing of the soil slurry and soil compression after de-watering, significantly deteriorates physical properties of soil compared to those of non-remediated soil. Furthermore, changed physical characteristics of remediated soil influence interaction of plant roots with soil system and affect soil water regime. Remediated soils showed significant differences to their original state in water retention properties and changed structure due to the influence of artificial structure created during remediation process. Disturbed and undisturbed soil samples of remediated and original soils were analyzed. We evaluated soil hydraulic properties as a possible constraint for re-establishing soil structure and soil fertility after the remediation procedure.

Welcome to Pacific Earthquake Engineering Research Center - PEER

Science.gov Websites

Triggering and Effects at Silty Soil Sites" - PEER Research Project Highlight: "Dissipative Base ; Upcoming Events More June 10-13, 2018 Geotechnical Earthquake Engineering and Soil Dynamics V 2018 - Call

Determination of medium electrical properties through full-wave modelling of frequency domain reflectrometry data

NASA Astrophysics Data System (ADS)

André, Frédéric; Lambot, Sébastien

2015-04-01

Accurate knowledge of the shallow soil properties is of prime importance in agricultural, hydrological and environmental engineering. During the last decade, numerous geophysical techniques, either invasive or resorting to proximal or remote sensing, have been developed and applied for quantitative characterization of soil properties. Amongst them, time domain reflectrometry (TDR) and frequency domain reflectometry (FDR) are recognized as standard techniques for the determination of soil dielectric permittivity and electrical conductivity, based on the reflected electromagnetic waves from a probe inserted into the soil. TDR data were first commonly analyzed in the time domain using methods considering only a part of the waveform information. Later, advancements have led to the possibility of analyzing the TDR signal through full-wave inverse modeling either in the time or the frequency domains. A major advantage of FDR compared to TDR is the possibility to increase the bandwidth, thereby increasing the information content of the data and providing more detailed characterization of the medium. Amongst the recent works in this field, Minet et al. (2010) developed a modeling procedure for processing FDR data based on an exact solution of Maxwell's equations for wave propagation in one-dimensional multilayered media. In this approach, the probe head is decoupled from the medium and is fully described by characteristic transfer functions. The authors successfully validated the method for homogeneous sand subject to a range of water contents. In the present study, we further validated the modelling approach using reference liquids with well-characterized frequency-dependent electrical properties. In addition, the FDR model was coupled with a dielectric mixing model to investigate the ability of retrieving water content, pore water electrical conductivity and sand porosity from inversion of FDR data acquired in sand subject to different water content levels. Finally, the possibility of reconstructing the vertical profile of the properties by inversion of FDR data collected during progressive insertion of the probe into a vertically heterogeneous medium was also investigated. Index Terms: Frequency domain reflectrometry (FDR), frequency dependence, dielectric permittivity, electrical conductivity Reference: Minet J., Lambot S., Delaide G., Huisman J.A., Vereecken H., Vanclooster M., 2010. A generalized frequency domain reflectometry modeling technique for soil electrical properties determination. Vadose Zone Journal, 9: 1063-1072.

Sensitivity of drainage efficiency of cranberry fields to edaphic conditions

NASA Astrophysics Data System (ADS)

Periard, Yann; José Gumiere, Silvio; Rousseau, Alain N.; Caron, Jean; Hallema, Dennis W.

2014-05-01

Water management on a cranberry farm requires intelligent irrigation and drainage strategies to sustain strong productivity and minimize environmental impact. For example, to avoid propagation of disease and meet evapotranspiration demand, it is imperative to maintain optimal moisture conditions in the root zone, which depends on an efficient drainage system. However, several drainage problems have been identified in cranberry fields. Most of these drainage problems are due to the presence of a restrictive layer in the soil profile (Gumiere et al., 2014). The objective of this work is to evaluate the effects of a restrictive layer on the drainage efficiency by the bias of a multi-local sensitivity analysis. We have tested the sensitivity of the drainage efficiency to different input parameters set of soil hydraulic properties, geometrical parameters and climatic conditions. Soil water flux dynamic for every input parameters set was simulated with finite element model Hydrus 1D (Simanek et al., 2008). Multi-local sensitivity was calculated with the Gâteaux directional derivatives with the procedure described by Cheviron et al. (2010). Results indicate that drainage efficiency is more sensitive to soil hydraulic properties than geometrical parameters and climatic conditions. Then, the geometrical parameters of the depth are more sensitive than the thickness. The drainage efficiency was very insensitive to the climatic conditions. Understanding the sensitivity of drainage efficiency according to soil hydraulic properties, geometrical and climatic conditions are essential for diagnosis drainage problems. However, it becomes important to identify the mechanisms involved in the genesis of anthropogenic soils cranberry to identify conditions that may lead to the formation of a restrictive layer. References: Cheviron, B., S.J. Gumiere, Y. Le Bissonnais, R. Moussa and D. Raclot. 2010. Sensitivity analysis of distributed erosion models: Framework. Water Resources Research 46: W08508. doi:10.1029/2009WR007950. Gumiere, S.J., J. Lafond, D. W. Hallema, Y. Périard, J. Caron et J. Gallichand. 2014. Mapping soil hydraulic conductivity and matric potential for water management of cranberry: Characterization and spatial interpolation methods. Biosystems Engineering.

EFFECT OF SOIL PROPERTIES ON LEAD BIOAVAILABILITY AND TOXCITY TO EARTHWORMS

EPA Science Inventory

Soil properties are important factors modifying metal bioavailability to ecological receptors. Twenty-one soils with a wide range of soil properties were amended with a single concentration of Pb (2000 mg/kg) to determine the effects of soil properties on Pb bioavailability and ...

Characterization of biosurfactants from indigenous soil bacteria recovered from oil contaminated sites.

PubMed

Kumar, Govind; Kumar, Rajesh; Sharma, Anita

2015-09-01

Three bacterial isolates (G1, G2 and G3) characterized as Pseudomonas plecoglossicida, Lysinibacillus fusiformis and Bacillus safensis were recovered from contaminated soil of oil refinery. These bacterial isolates produced biosurfactants in MSM medium in stationary phase. Biosurfactants were characterized on the basis of their emulsifying properties with petrol, diesel, mobil oil and petrol engine oil. Reduction in surface tension (below 40 mN m(-1)) and blood hemolysis were also included in biosurfactants characterization. Emulsification indices of G1, G2 and G3 were in the range of 98.82, 23.53 and 58.82 for petrol; 29.411,1.05 and 70.588 for diesel; 35.31, 2.93 and 17.60 for mobil oil and 35.284, 58.82 and 17.647 for petrol engine oil respectively. Dry weight of the extracted biosurfactant was 4.6, 1.4 and 2.4 g I(-1) for G1, G2 and G3 respectively. Structural analysis of the biosurfactants by Fourier Transform Infrared Spectroscopy (FTIR) revealed significant differences in the bonding pattern of individual biosurfactant.

Studying the effects of wildfires on soils (or how to get smudged with ash)

NASA Astrophysics Data System (ADS)

Jordán, Antonio

2015-04-01

I work in the Department of Crystallography, Mineralogy and Agricultural Chemistry at the University of Seville, where I coordinate the MED_Soil Research Group since 2008, which is affiliated to the department of Crystallography, Mineralogy and Agricultural Chemistry (University of Sevilla). The group is formed by a multidisciplinary stable team of researchers (biologists, chemists, geomorphologists, geographers, physicists and agricultural engineers), collaborators, auxiliary staff, students and staff associated to research projects. Other involved researchers belong to the University of Córdoba, University Miguel Hernández, the University of Valencia and the Institute for Natural Resources and Agrobiology of Sevilla (IRNAS/CSIC), in Spain, the University of Western Australia (Australia), University of Algarve (Portugal), Mykolas Romeris University (Lithuania), Michoacan University San Nicolás de Hidalgo (México), University of Naples (Italy) and the National Research Centre of Cairo (Egypt). In general, my research lines include the study of rainfall-induced soil erosion processes, the effects of wildfires on soil properties and soil degradation in Mediterranean areas. Fires are frequent and recurrent phenomena in Mediterranean ecosystems, with several ecological and environmental impacts caused in part by short and medium-term effects on soil physical, chemical and biological characteristics as well as on organic matter composition, properties and dynamics. Altered fire regimes negatively affect soil health and quality favouring the occurrence of erosive processes and the loose of a non renewable natural resource. Also, due to the large carbon pool present in soils, small variations in soil organic matter content may have a significant effect in the biogeochemical cycles and on the global climate change. As a consequence of fire, new forms and thermal modifications of organic molecules lead to the formation of substances with weak colloidal properties and enhanced resistance to chemical and biological degradation. An example of the impact of the reorganization and translocation of organic molecules in the soil is the appearance of soil water repellency. The accumulation of certain organic compounds such as aliphatic hydrocarbons and amphiphilic compounds, are responsible for soil water repellency. Translocation and concentration of organic substances during burning may contribute to generate a water-repellent soil layer. In that case, water infiltration may be inhibited or delayed during periods of time between a few seconds and hours or days (if extreme repellency exists). Water repellency has great implications on soil behaviour. Delayed infiltration contributes to enhanced runoff rates and accelerated water erosion processes, increasing water and nutrient losses by the generation of preferential flow paths, limiting plant production and affecting microbial activity and germination. However, the effects of fire on soil are reversible. Under natural fire regimes, soil properties may naturally return to a situation close to the initial one in a variable period of time. But restoration of burned areas is complicated, as there is not an unique answer. Too often, decision-makers apply the same measures to different situations, regardless of the severity of the fire, natural conditions or the ability of soil and vegetation to regenerate themselves. For this reason, it is necessary to study and understand in detail the processes that are triggered in fire-affected soils in order to provide adequate responses to each situation. An early detection of soil recovery is important for decision making and planning of environmental restoration actions in the postfire.

System reliability analysis of granular filter for protection against piping in dams

NASA Astrophysics Data System (ADS)

Srivastava, A.; Sivakumar Babu, G. L.

2015-09-01

Granular filters are provided for the safety of water retaining structure for protection against piping failure. The phenomenon of piping triggers when the base soil to be protected starts migrating in the direction of seepage flow under the influence of seepage force. To protect base soil from migration, the voids in the filter media should be small enough but it should not also be too small to block smooth passage of seeping water. Fulfilling these two contradictory design requirements at the same time is a major concern for the successful performance of granular filter media. Since Terzaghi era, conventionally, particle size distribution (PSD) of granular filters is designed based on particle size distribution characteristics of the base soil to be protected. The design approach provides a range of D15f value in which the PSD of granular filter media should fall and there exist infinite possibilities. Further, safety against the two critical design requirements cannot be ensured. Although used successfully for many decades, the existing filter design guidelines are purely empirical in nature accompanied with experience and good engineering judgment. In the present study, analytical solutions for obtaining the factor of safety with respect to base soil particle migration and soil permeability consideration as proposed by the authors are first discussed. The solution takes into consideration the basic geotechnical properties of base soil and filter media as well as existing hydraulic conditions and provides a comprehensive solution to the granular filter design with ability to assess the stability in terms of factor of safety. Considering the fact that geotechnical properties are variable in nature, probabilistic analysis is further suggested to evaluate the system reliability of the filter media that may help in risk assessment and risk management for decision making.

Terrain physical properties derived from orbital data and the first 360 sols of Mars Science Laboratory Curiosity rover observations in Gale Crater

NASA Astrophysics Data System (ADS)

Arvidson, R. E.; Bellutta, P.; Calef, F.; Fraeman, A. A.; Garvin, J. B.; Gasnault, O.; Grant, J. A.; Grotzinger, J. P.; Hamilton, V. E.; Heverly, M.; Iagnemma, K. A.; Johnson, J. R.; Lanza, N.; Le Mouélic, S.; Mangold, N.; Ming, D. W.; Mehta, M.; Morris, R. V.; Newsom, H. E.; Rennó, N.; Rubin, D.; Schieber, J.; Sletten, R.; Stein, N. T.; Thuillier, F.; Vasavada, A. R.; Vizcaino, J.; Wiens, R. C.

2014-06-01

Physical properties of terrains encountered by the Curiosity rover during the first 360 sols of operations have been inferred from analysis of the scour zones produced by Sky Crane Landing System engine plumes, wheel touch down dynamics, pits produced by Chemical Camera (ChemCam) laser shots, rover wheel traverses over rocks, the extent of sinkage into soils, and the magnitude and sign of rover-based slippage during drives. Results have been integrated with morphologic, mineralogic, and thermophysical properties derived from orbital data, and Curiosity-based measurements, to understand the nature and origin of physical properties of traversed terrains. The hummocky plains (HP) landing site and traverse locations consist of moderately to well-consolidated bedrock of alluvial origin variably covered by slightly cohesive, hard-packed basaltic sand and dust, with both embedded and surface-strewn rock clasts. Rock clasts have been added through local bedrock weathering and impact ejecta emplacement and form a pavement-like surface in which only small clasts (<5 to 10 cm wide) have been pressed into the soil during wheel passages. The bedded fractured (BF) unit, site of Curiosity's first drilling activity, exposes several alluvial-lacustrine bedrock units with little to no soil cover and varying degrees of lithification. Small wheel sinkage values (<1 cm) for both HP and BF surfaces demonstrate that compaction resistance countering driven-wheel thrust has been minimal and that rover slippage while traversing across horizontal surfaces or going uphill, and skid going downhill, have been dominated by terrain tilts and wheel-surface material shear modulus values.

Field Identification of Andic Soil Properties for Soils of North-central Idaho

Treesearch

Brian Gardner

2007-01-01

Currently, laboratory measurements are definitive for identifying andic soil properties in both the USDA Soil Taxonomy (Soil Survey Staff 1999) and the World Reference Base for Soil Resources (FAO/ISRIC/ISSS 1998). Andic soil properties, as described in Soil Taxonomy, result mainly from the presence of significant amounts of allophone, imogolite, ferrihydrite or...

Physical properties of forest soils

Treesearch

Charles H. Perry; Michael C. Amacher

2007-01-01

Why Are Physical Properties of the Soil Important? The soil quality indicator, when combined with other data collected by the FIA program, can indicate the current rates of soil erosion, the extent and intensity of soil compaction, and some basic physical properties of the forest floor and the top 20 cm of soil. In this report, two particular physical properties of the...

Impact of surface coal mining on soil hydraulic properties

Treesearch

X. Liu; J. Q. Wu; P. W. Conrad; S. Dun; C. S. Todd; R. L. McNearny; William Elliot; H. Rhee; P. Clark

2016-01-01

Soil erosion is strongly related to soil hydraulic properties. Understanding how surface coal mining affects these properties is therefore important in developing effective management practices to control erosion during reclamation. To determine the impact of mining activities on soil hydraulic properties, soils from undisturbed areas, areas of roughly graded mine...

Arsenic bioavailability in soils before and after soil washing: the use of Escherichia coli whole-cell bioreporters.

PubMed

Yoon, Youngdae; Kang, Yerin; Chae, Yooeun; Kim, Sunghoon; Lee, Youngshim; Jeong, Seung-Woo; An, Youn-Joo

2016-02-01

We investigated the quantification of bioavailable arsenic in contaminated soils and evaluation of soil-washing processes in the aspect of bioavailability using a novel bacterial bioreporter developed in present study. The whole-cell bioreporter (WCB) was genetically engineered by fusing the promoter of nik operon from Escherichia coli and green fluorescent protein as a sensing domain and reporter domain. Among eight well-known hazardous heavy metals and metalloid, this system responded specifically to arsenic, thereby inferring association of As(III) with NikR inhibits the repression. Moreover, the response was proportional to the concentration of As(III), thereby it was capable to determine the amount of bioavailable arsenic quantitatively in contaminated soils. The bioavailable portion of arsenic was 5.9 (3.46-10.96) and 0.9 (0.27-1.74) % of total from amended and site soils, respectively, suggesting the bioavailability of arsenic in soils was related to the soil properties and duration of aging. On the other hand, only 1.37 (0.21-2.97) % of total arsenic was extracted into soil solutions and 19.88 (11.86-28.27) % of arsenic in soil solution was bioavailable. This result showed that the soluble arsenic is not all bioavailable and most of bioavailable arsenic in soils is water non-extractable. In addition, the bioavailable arsenic was increased after soil-washing while total amount was decreased, thereby suggesting the soil-washing processes release arsenic associated with soil materials to be bioavailable. Therefore, it would be valuable to have a tool to assess bioavailability and the bioavailability should be taken into consideration for soil remediation plans.

Basic Soils. Revision.

ERIC Educational Resources Information Center

Montana State Univ., Bozeman. Dept. of Agricultural and Industrial Education.

This curriculum guide is designed for use in teaching a course in basic soils that is intended for college freshmen. Addressed in the individual lessons of the unit are the following topics: the way in which soil is formed, the physical properties of soil, the chemical properties of soil, the biotic properties of soil, plant-soil-water…

Conceptional Considerations to Energy Balance and Global Warming Potential of Soil Bioengineering Structures

NASA Astrophysics Data System (ADS)

von der Thannen, Magdalena; Paratscha, Roman; Smutny, Roman; Lampalzer, Thomas; Strauss, Alfred; Rauch, Hans Peter

2016-04-01

Nowadays there is a high demand on engineering solutions considering not only technical aspects but also ecological and aesthetic values. In this context soil bioengineering techniques are often used as standalone solutions or in combination with conventional engineering structures. It is a construction technique that uses biological components for hydraulic and civil engineering solutions. In general it pursues the same objectives as conventional civil engineering structures. Currently the used assessment methods for soil bioengineering structures are referencing technically, ecologically and socio-economically. In a modern engineering approach additionally, environmental impacts and potential added values should be considered. The research project E-Protect aims at developing Environmental Life Cycle Assessment (LCA) models for this special field of alpine protective constructions. Both, the Cumulative Energy Demand (CED) and the Global Warming Potential (GWP) should be considered in an Environmental LCA over the whole life cycle of an engineering structure. The life cycle itself can be divided into three phases: the construction phase, the use phase and the end of life phase. The paper represents a concept to apply an Environmental LCA model for soil bioengineering structures. Beside the construction phase of these structures particular attention will be given to the use phase. It is not only important in terms of engineering effects but also plays an important role for positive carbon footprint due to the growing plants of soil bioengineering structures in contrast to conventional structures. Innovative Environmental LCA models will be applied to soil bioengineering structures which provide a new transparency for the responsible planners and stakeholders, by pointing out the total consumption of resources in all construction phases and components.

The use of FDEM in hydrogeophysics: A review

NASA Astrophysics Data System (ADS)

Boaga, Jacopo

2017-04-01

Hydrogeophysics is a rapidly evolving discipline emerging from geophysical methods. Geophysical methods are nowadays able to illustrate not only the fabric and the structure of the underground, but also the subsurface processes that occur within it, as fluids dynamic and biogeochemical reactions. This is a growing wide inter-disciplinary field, specifically dedicated to revealing soil properties and monitoring processes of change due to soil/bio/atmosphere interactions. The discipline involves environmental, hydrological, agricultural research and counts application for several engineering purposes. The most frequently used techniques in the hydrogeophysical framework are the electric and electromagnetic methods because they are highly sensitive to soil physical properties such as texture, salinity, mineralogy, porosity and water content. Non-invasive techniques are applied in a number of problems related to characterization of subsurface hydrology and groundwater dynamic processes. Ground based methods, as electrical tomography, proved to obtain considerable resolution but they are difficult to extend to wider exploration purposes due to their logistical limitation. Methods that don't need electrical contact with soil can be, on the contrary, easily applied to broad areas. Among these methods, a rapidly growing role is played by frequency domain electro-magnetic (FDEM) survey. This is due thanks to the improvement of multi-frequency and multi-coils instrumentation, simple time-lapse repeatability, cheap and accurate topographical referencing, and the emerging development of inversion codes. From raw terrain apparent conductivity meter, FDEM survey is becoming a key tool for 3D soil characterization and dynamics observation in near surface hydrological studies. Dozens of papers are here summarized and presented, in order to describe the promising potential of the technique.

Combining ground penetrating radar and electromagnetic induction for industrial site characterization

NASA Astrophysics Data System (ADS)

Van De Vijver, Ellen; Van Meirvenne, Marc; Saey, Timothy; De Smedt, Philippe; Delefortrie, Samuël; Seuntjens, Piet

2014-05-01

Industrial sites pose specific challenges to the conventional way of characterizing soil and groundwater properties through borehole drilling and well monitoring. The subsurface of old industrial sites typically exhibits a large heterogeneity resulting from various anthropogenic interventions, such as the dumping of construction and demolition debris and industrial waste. Also larger buried structures such as foundations, utility infrastructure and underground storage tanks are frequently present. Spills and leaks from industrial activities and leaching of buried waste may have caused additional soil and groundwater contamination. Trying to characterize such a spatially heterogeneous medium with a limited number of localized observations is often problematic. The deployment of mobile proximal soil sensors may be a useful tool to fill up the gaps in between the conventional observations, as these enable measuring soil properties in a non-destructive way. However, because the output of most soil sensors is affected by more than one soil property, the application of only one sensor is generally insufficient to discriminate between all contributing factors. To test a multi-sensor approach, we selected a study area which was part of a former manufactured gas plant site located in one of the seaport areas of Belgium. It has a surface area of 3400 m² and was the location of a phosphate production unit that was demolished at the end of the 1980s. Considering the long and complex history of the site we expected to find a typical "industrial" soil. Furthermore, the studied area was located between buildings of the present industry, entailing additional practical challenges such as the presence of active utilities and aboveground obstacles. The area was surveyed using two proximal soil sensors based on two different geophysical methods: ground penetrating radar (GPR), to image contrasts in dielectric permittivity, and electromagnetic induction (EMI), to measure the apparent soil electrical conductivity (ECa) and magnetic susceptibility (MSa). For both methods one of the latest-generation instruments was used. GPR data were collected using a 3d-Radar stepped-frequency system with multi-channel antenna design. For EMI, this was the multi-receiver DUALEM-21S sensor. This sensor contains four different transmitter-receiver coil pair configurations, which allows to record the ECa and MSa for four different soil volumes at the same time, thereby providing information about the vertical variation of these soil properties. Both the EMI and GPR survey were performed in a mobile set-up with real-time georeferencing to obtain a high-resolution coverage of the area. The results of both surveys were validated with conventional site characterization that was conducted for a soil contamination investigation, and ancillary information such as aerial photographs and utility maps. Both methods were compared on their performance in detecting different types of anomalies. We report on the successes and failures with this multi-sensor approach. The authors acknowledge funding by COST Action TU1208 "Civil Engineering Applications of Ground Penetrating Radar"

3D Bedrock Structure of Bornova Plain and Its surroundings (İzmir/Western Turkey)

NASA Astrophysics Data System (ADS)

Pamuk, Eren; Gönenç, Tolga; Özdağ, Özkan Cevdet; Akgün, Mustafa

2018-01-01

An earthquake record is needed on engineering bedrock to perform soil deformation analysis. This record could be obtained in different ways (seismographs on engineering bedrock; by the help of the soil transfer function; scenario earthquakes). S-wave velocity ( V s) profile must be known at least till engineering bedrock for calculating soil transfer functions true and completely. In addition, 2D or 3D soil, engineering-seismic bedrock models are needed for soil response analyses to be carried out. These models are used to determine changes in the amplitude and frequency content of earthquake waves depending on the seismic impedance from seismic bedrock to the ground surface and the basin effects. In this context, it is important to use multiple in situ geophysical techniques to create the soil-bedrock models. In this study, 2D and 3D soil-bedrock models of Bornova plain and its surroundings (Western Turkey), which are very risky in terms of seismicity, were obtained by combined survey of surface wave and microgravity methods. Results of the study show that the engineering bedrock depths in the middle part of Bornova plain range from 200 to 400 m and the southern and northern parts which are covered limestone and andesite show the engineering bedrock ( V s > 760 m/s) feature. In addition, seismic bedrock ( V s < 3000 m/s) depth changes from 550 to 1350 m. The predominant period values obtained from single station microtremor method change from 0.45 to 1.6 s while they are higher than 1 s in the middle part of Bornova plain where the basin is deeper. Bornova Plain has a very thick sediment units which have very low V s values above engineering bedrock. In addition, it is observed sudden changes at the interfaces of the layer in horizontal and vertical directions.

Development and Validation of EPH Material Model for Engineered Roadway Soil

DTIC Science & Technology

2014-08-01

MODEL FOR ENGINEERED ROADWAY SOIL Ching Hsieh, PhD Altair Engineering Troy, MI Jianping Sheng, Ph.D. Jai Ramalingam System Engineering...0188 Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing...of information if it does not display a currently valid OMB control number. 1 . REPORT DATE 11 AUG 2014 2. REPORT TYPE Journal Article 3. DATES

Determining Wheel-Soil Interaction Loads Using a Meshfree Finite Element Approach Assisting Future Missions with Rover Wheel Design

NASA Technical Reports Server (NTRS)

Contreras, Michael T.; Peng, Chia-Yen; Wang, Dongdong; Chen, Jiun-Shyan

2012-01-01

A wheel experiencing sinkage and slippage events poses a high risk to rover missions as evidenced by recent mobility challenges on the Mars Exploration Rover (MER) project. Because several factors contribute to wheel sinkage and slippage conditions such as soil composition, large deformation soil behavior, wheel geometry, nonlinear contact forces, terrain irregularity, etc., there are significant benefits to modeling these events to a sufficient degree of complexity. For the purposes of modeling wheel sinkage and slippage at an engineering scale, meshfree finite element approaches enable simulations that capture sufficient detail of wheel-soil interaction while remaining computationally feasible. This study demonstrates some of the large deformation modeling capability of meshfree methods and the realistic solutions obtained by accounting for the soil material properties. A benchmark wheel-soil interaction problem is developed and analyzed using a specific class of meshfree methods called Reproducing Kernel Particle Method (RKPM). The benchmark problem is also analyzed using a commercially available finite element approach with Lagrangian meshing for comparison. RKPM results are comparable to classical pressure-sinkage terramechanics relationships proposed by Bekker-Wong. Pending experimental calibration by future work, the meshfree modeling technique will be a viable simulation tool for trade studies assisting rover wheel design.

Open charcoal chamber method for mass measurements of radon exhalation rate from soil surface.

PubMed

Tsapalov, Andrey; Kovler, Konstantin; Miklyaev, Peter

2016-08-01

Radon exhalation rate from the soil surface can serve as an important criterion in the evaluation of radon hazard of the land. Recently published international standard ISO 11665-7 (2012) is based on the accumulation of radon gas in a closed container. At the same time since 1998 in Russia, as a part of engineering and environmental studies for the construction, radon flux measurements are made using an open charcoal chamber for a sampling duration of 3-5 h. This method has a well-defined metrological justification and was tested in both favorable and unfavorable conditions. The article describes the characteristics of the method, as well as the means of sampling and measurement of the activity of radon absorbed. The results of the metrological study suggest that regardless of the sampling conditions (weather, the mechanism and rate of radon transport in the soil, soil properties and conditions), uncertainty of method does not exceed 20%, while the combined standard uncertainty of radon exhalation rate measured from the soil surface does not exceed 30%. The results of the daily measurements of radon exhalation rate from the soil surface at the experimental site during one year are reported. Copyright © 2016 Elsevier Ltd. All rights reserved.

Climate-change effects on soils: Accelerated weathering, soil carbon and elemental cycling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qafoku, Nikolla

2015-04-01

Climate change [i.e., high atmospheric carbon dioxide (CO2) concentrations (≥400 ppm); increasing air temperatures (2-4°C or greater); significant and/or abrupt changes in daily, seasonal, and inter-annual temperature; changes in the wet/dry cycles; intensive rainfall and/or heavy storms; extended periods of drought; extreme frost; heat waves and increased fire frequency] is and will significantly affect soil properties and fertility, water resources, food quantity and quality, and environmental quality. Biotic processes that consume atmospheric CO2, and create organic carbon (C) that is either reprocessed to CO2 or stored in soils are the subject of active current investigations, with great concern over themore » influence of climate change. In addition, abiotic C cycling and its influence on the inorganic C pool in soils is a fundamental global process in which acidic atmospheric CO2 participates in the weathering of carbonate and silicate minerals, ultimately delivering bicarbonate and Ca2+ or other cations that precipitate in the form of carbonates in soils or are transported to the rivers, lakes, and oceans. Soil responses to climate change will be complex, and there are many uncertainties and unresolved issues. The objective of the review is to initiate and further stimulate a discussion about some important and challenging aspects of climate-change effects on soils, such as accelerated weathering of soil minerals and resulting C and elemental fluxes in and out of soils, soil/geo-engineering methods used to increase C sequestration in soils, soil organic matter (SOM) protection, transformation and mineralization, and SOM temperature sensitivity. This review reports recent discoveries, identifies key research needs, and highlights opportunities offered by the climate-change effects on soils.« less

Breaking ground: Pedological, geological, and ecological implications of soil bioturbation

NASA Astrophysics Data System (ADS)

Wilkinson, Marshall T.; Richards, Paul J.; Humphreys, Geoff S.

Soil and its biota are fundamental components of the "Critical Zone": Earth's living skin that most directly sustains life. Within that zone, geologically-rapid soil and saprolite displacement by biota, particularly invertebrate meso- and macrofauna, affects a large proportion of Earth's soils. This was first recognised by late-19th century observers, on both sides of the Atlantic Ocean, who regarded bioturbation as fundamental to soil formation. Throughout much of the 20th century, however, the agronomical focus of soil scientists and the dominant paradigm of landscape evolution relegated bioturbation. As a result, many aspects of bioturbation are still not widely appreciated. Only in the last few decades has a re-evaluation commenced, in a range of disciplines. Primary effects of bioturbation, which we quantify herein, include soil production from saprolite, the formation of surface mounds, soil burial, and downslope transport. Rates of bioturbation can be as rapid as sustained maximum rates of tectonic uplift. In concert with surface geomorphic processes, bioturbation alters fundamental properties of soil, including particle-size distribution, porosity, the content of carbon and other nutrients, and creep flux rate. The precise influence of biotic mixing is regulated by its depth function. Earth's incredibly diverse soil biota also perform a number of functions, at a range of spatial and temporal scales, that extend beyond soil to landscape evolution, ecosystem engineering, niche construction, and carbon cycling. Understanding these linkages—which have operated since the evolution of trees in the Devonian Period—is of growing importance as we seek a fuller picture of Earth's history to predict and manage its future.

A quantitative comparison of Soil Development in four climatic regimes

USGS Publications Warehouse

Harden, J.W.; Taylor, E.M.

1983-01-01

A new quantitative Soil Development Index based on field data has been applied to chronosequences formed under different climatic regimes. The four soil chronosequences, developed primarily on sandy deposits, have some numeric age control and are located in xeric-inland (Merced, Calif.), xeric-coastal (Ventura, Calif.), aridic (Las Cruces, N. Mex.), and udic (Susquehanna Valley, Pa.) soil-moisture regimes. To quantify field properties, points are assigned for developmental increases in soil properties in comparison to the parent material. Currently ten soil-field properties are quantified and normalized for each horizon in a given chronosequence, including two new properties for carbonate-rich soils in addition to the eight properties previously defined. When individual properties or the combined indexes are plotted as a function of numeric age, rates of soil development can be compared in different climates. The results demonstrate that (1) the Soil Development Index can be applied to very different soil types, (2) many field properties develop systematically in different climatic regimes, (3) certain properties appear to have similar rates of development in different climates, and (4) the Profile Index that combines different field properties increases significantly with age and appears to develop at similar rates in different climates. The Soil Development Index can serve as a preliminary guide to soil age where other age control is lacking and can be used to correlate deposits of different geographical and climatic regions. ?? 1983.

Transport of soil-aged silver nanoparticles in unsaturated sand.

PubMed

Kumahor, Samuel K; Hron, Pavel; Metreveli, George; Schaumann, Gabriele E; Klitzke, Sondra; Lang, Friederike; Vogel, Hans-Jörg

2016-12-01

Engineered nanoparticles released into soils may be coated with humic substances, potentially modifying their surface properties. Due to their amphiphilic nature, humic coating is expected to affect interaction of nanoparticle at the air-water interface. In this study, we explored the roles of the air-water interface and solid-water interface as potential sites for nanoparticle attachment and the importance of hydrophobic interactions for nanoparticle attachment at the air-water interface. By exposing Ag nanoparticles to soil solution extracted from the upper soil horizon of a floodplain soil, the mobility of the resulting "soil-aged" Ag nanoparticles was investigated and compared with the mobility of citrate-coated Ag nanoparticles as investigated in an earlier study. The mobility was determined as a function of hydrologic conditions and solution chemistry using column breakthrough curves and numerical modeling. Specifically, we compared the mobility of both types of nanoparticles for different unsaturated flow conditions and for pH=5 and pH=9. The soil-aged Ag NP were less mobile at pH=5 than at pH=9 due to lower electrostatic repulsion at pH=5 for both types of interfaces. Moreover, the physical flow field at different water contents modified the impact of chemical forces at the solid-water interface. An extended Derjaguin-Landau-Verwey-Overbeek (eDLVO) model did not provide satisfactory explanation of the observed transport phenomena unlike for the citrate-coated case. For instance, the eDLVO model assuming sphere-plate geometry predicts a high energy barrier (>90 kT) for the solid-water interface, indicating that nanoparticle attachment is less likely. Furthermore, retardation through reversible sorption at the air-water interface was probably less relevant for soil-aged nanoparticles than for citrate-coated nanoparticles. An additional cation bridging mechanism and straining within the flow field may have enhanced nanoparticle retention at the solid-water interface. The results indicate that the mobility of engineered Ag nanoparticles is sensitive to solution chemistry, especially pH and the concentration of multivalent cations, and to the unsaturated flow conditions influencing particle interaction at biogeochemical interfaces. Copyright © 2016 Elsevier B.V. All rights reserved.

Transport of soil-aged silver nanoparticles in unsaturated sand

NASA Astrophysics Data System (ADS)

Kumahor, Samuel K.; Hron, Pavel; Metreveli, George; Schaumann, Gabriele E.; Klitzke, Sondra; Lang, Friederike; Vogel, Hans-Jörg

2016-12-01

Engineered nanoparticles released into soils may be coated with humic substances, potentially modifying their surface properties. Due to their amphiphilic nature, humic coating is expected to affect interaction of nanoparticle at the air-water interface. In this study, we explored the roles of the air-water interface and solid-water interface as potential sites for nanoparticle attachment and the importance of hydrophobic interactions for nanoparticle attachment at the air-water interface. By exposing Ag nanoparticles to soil solution extracted from the upper soil horizon of a floodplain soil, the mobility of the resulting ;soil-aged; Ag nanoparticles was investigated and compared with the mobility of citrate-coated Ag nanoparticles as investigated in an earlier study. The mobility was determined as a function of hydrologic conditions and solution chemistry using column breakthrough curves and numerical modeling. Specifically, we compared the mobility of both types of nanoparticles for different unsaturated flow conditions and for pH = 5 and pH = 9. The soil-aged Ag NP were less mobile at pH = 5 than at pH = 9 due to lower electrostatic repulsion at pH = 5 for both types of interfaces. Moreover, the physical flow field at different water contents modified the impact of chemical forces at the solid-water interface. An extended Derjaguin-Landau-Verwey-Overbeek (eDLVO) model did not provide satisfactory explanation of the observed transport phenomena unlike for the citrate-coated case. For instance, the eDLVO model assuming sphere-plate geometry predicts a high energy barrier (> 90 kT) for the solid-water interface, indicating that nanoparticle attachment is less likely. Furthermore, retardation through reversible sorption at the air-water interface was probably less relevant for soil-aged nanoparticles than for citrate-coated nanoparticles. An additional cation bridging mechanism and straining within the flow field may have enhanced nanoparticle retention at the solid-water interface. The results indicate that the mobility of engineered Ag nanoparticles is sensitive to solution chemistry, especially pH and the concentration of multivalent cations, and to the unsaturated flow conditions influencing particle interaction at biogeochemical interfaces.

Soils as records of past and present environments

NASA Astrophysics Data System (ADS)

Sauer, Daniela

2015-04-01

This contribution reflects selected pedological concepts that are helpful for interpreting soil properties related to past and present environments. These concepts are illustrated by examples from various landscapes, and their combination finally leads to some further conclusions. The concept of Targulian and Gerasimova (2009) distinguishes soil system and soil body. Soil system is defined as "open multiphase system functioning in any solid-phase substrate at its interface with the atmosphere, hydrosphere and biota", and soil body as "solid-phase part of a soil system produced by its long-term functioning and composed of a vertical sequence of genetic horizons". Soil system functioning corresponds to the recent environmental factors and includes heat and moisture dynamics, biomass production, biogeochemical cycles, and other processes. In contrast, a soil body is a record of the long-term functioning of a soil system. It thus provides a record not only of the functioning of the soil system under the present environmental conditions but also under past, possibly different, conditions. Hence, Targulian and Goryachkin (2004) called it the "memory" of the landscape. Richter and Yaalon (2012) argued that most soils comprise both, features that developed under the present environmental conditions and features that reflect different conditions that the soils experienced in the past; they concluded that most soils are polygenetic. Although the current functioning of the soil system in the concept of Targulian and Gerasimova (2009) is mainly controlled by the present-day combination of environmental factors, it should be added that past processes also influence the soil system, because past processes changed the soil properties in a way that also the present-day functioning of the soil system is affected by these changes. Earlier, Yaalon (1971) had categorised soil properties according to the time-span required for their adjustment to the actual environment, distinguishing (i) rapidly adjusting soil properties (adjusting within some hundreds of years), (ii) slowly adjusting soil properties (adjusting within some thousands of years), and (iii) persistent soil properties (showing no changes over ten thousands to millions of years). In a polygenetic soil, rapidly adjusting soil properties may already be in equilibrium with the present conditions, whereas slowly adjusting soil properties may still reflect past conditions. Thus, the lower the rate at which a certain soil property in a polygenetic soil adjusts, the larger is the extent to which this property is still determined by earlier environmental conditions. Knowledge on the rates at which soil properties adjust may hence be used to estimate the time at which a significant environmental change took place, based on the degree of overprinting of the different kinds of soil properties adjusting at different rates in a polygenetic soil. References: Richter, D. de B., Yaalon, D.H., 2012. "The changing model of soil" revisited. Soil Sci. Soc. Am. J. 76, 766-778. Targulian, V. O., Goryachkin, S. V., 2004. Soil memory: Types of records, carriers, hierarchy and diversity. Revista Mexicana Ciencias Geol. 21, 1-8. Targulian, V.O., Gerasimova, M., 2009. Soil geography: geography of soil systems and soil bodies. Soil Geography: New Horizons. International Conference, 16-20 November 2009 in Huatulco, Mexico. Book of abstracts, 39. Yaalon, D.H., 1971. Soil forming processes in time and space. In: Yaalon, D.H. (Ed.), Paleopedology-origin, nature and dating of paleosols. Int. Soc. Soil Sci. and Israel Univ. Press, Jerusalem, pp. 29-39.

Selected engineering properties and applications of EPS geofoam

NASA Astrophysics Data System (ADS)

Elragi, Ahmed Fouad

Expanded polystyrene (EPS) geofoam is a lightweight material that has been used in engineering applications since at least the 1950s. Its density is about a hundredth of that of soil. It has good thermal insulation properties with stiffness and compression strength comparable to medium clay. It is utilized in reducing settlement below embankments, sound and vibration damping, reducing lateral pressure on substructures, reducing stresses on rigid buried conduits and related applications. This study starts with an overview on EPS geofoam. EPS manufacturing processes are described followed by a review of engineering properties found in previous research work done so far. Standards and design manuals applicable to EPS are presented. Selected EPS geofoam-engineering applications are discussed with examples. State-of-the-art of experimental work is done on different sizes of EPS specimens under different loading rates for better understanding of the behavior of the material. The effects of creep, sample size, strain rate and cyclic loading on the stress strain response are studied. Equations for the initial modulus and the strength of the material under compression for different strain rates are presented. The initial modulus and Poisson's ratio are discussed in detail. Sample size effect on creep behavior is examined. Three EPS projects are shown in this study. The creep behavior of the largest EPS geofoam embankment fill is shown. Results from laboratory tests, mathematical modeling and field records are compared to each other. Field records of a geofoam-stabilized slope are compared to finite difference analysis results. Lateral stress reduction on an EPS backfill retaining structure is analyzed. The study ends with a discussion on two promising properties of EPS geofoam. These are the damping ability and the compressibility of this material. Finite element analysis, finite difference analysis and lab results are included in this discussion. The discussion with the rest of the study points towards the main conclusion that EPS geofoam is the future material of promise in various civil engineering applications.

An Index-Based Approach to Assessing Recalcitrance and Soil Carbon Sequestration Potential of Engineered Black Carbons (Biochars)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harvey, Omar R.; Kuo, Li-Jung; Zimmerman, Andrew R.

2012-01-10

The ability of engineered black carbons (or biochars) to resist abiotic and, or biotic degradation (herein referred to as recalcitrance) is crucial to their successful deployment as a soil carbon sequestration strategy. A new recalcitrance index, the R{sub 50}, for assessing biochar quality for carbon sequestration is proposed. The R{sub 50} is based on the relative thermal stability of a given biochar to that of graphite and was developed and evaluated with a variety of biochars (n = 59), and soot-like black carbons. Comparison of R{sub 50}, with biochar physicochemical properties and biochar-C mineralization revealed the existence of a quantifiablemore » relationship between R{sub 50} and biochar recalcitrance. As presented here, the R{sub 50} is immediately applicable to pre-land application screening of biochars into Class A (R{sub 50} {>=} 0.70), Class B (0.50 {<=} R{sub 50} < 0.70) or Class C (R{sub 50} < 0.50) recalcitrance/carbon sequestration classes. Class A and Class C biochars would have carbon sequestration potential comparable to soot/graphite and uncharred plant biomass, respectively, while Class B biochars would have intermediate carbon sequestration potential. We believe that the coupling of the R{sub 50}, to an index-based degradation, and an economic model could provide a suitable framework in which to comprehensively assess soil carbon sequestration in biochars.« less

“Wave - Particle Duality” and Soil Liquefaction in Geotechnical Engineering

NASA Astrophysics Data System (ADS)

Wang, Demin

2017-10-01

In the disaster situation of multi-earthquake, with the phenomenon of vibrating phenomenon and the occurrence of cracks in the surface soil, the collapse of the buildings on the ground are caused. The author tries to explain the phenomenon of earthquake disaster in this geotechnical engineering by using the wave-particle duality theory of sunlight. And proposed the sun in the physics of the already high frequency of the weak light superimposed into the low frequency of the low light wave volatility, once again superimposed, superimposed as a lower frequency of linear light, the energy from low to high. Sunlight from weak light into a strong sunlight, that is, the sun near the observation may be weak light or black sunspots is composed of black holes. By long distance, the convergence of light becomes into a dazzling luminous body. Light from the numerous light quantum and an energy line form a half-space infinite volatility curve, and the role of light plays under the linear form of particles. When the night is manifested of l black approaching unconnected light quantum. The author plays the earth as the sun, compared to the deep pressure of low-viscosity clay soil pore, water performance is complex. Similar to the surface of the sun’s spectrum, saturated silty sand is showed volatility, Ground surface high-energy clay showed particle properties. Particle performance is shear strength.

Evaluation of the effectiveness of olive cake residue as an expansive soil stabilizer

NASA Astrophysics Data System (ADS)

Nalbantoglu, Zalihe; Tawfiq, Salma

2006-08-01

The quantity of the by-product olive cake residue generated in most parts of the Mediterranean countries continues to increase and expected to double in amount within 10 15 years. This increase intensifies the problems associated with the disposal of this by-product. Olive cake residue has a potential for use as a soil stabilizer and large volumes can be beneficially used. This study is directed toward determining if olive cake residue can be utilized to increase the strength and stability of expansive soils which constitute a costly natural hazard to lightweight structures on shallow foundations. A series of laboratory tests using engineering properties, such as Atterberg limits, moisture-density relationship (compaction), swell, unconfined compressive strength were undertaken to evaluate the effectiveness and performance of the olive cake residue as a soil stabilizer. Test results indicate that an addition of only 3% burned olive waste into the soil causes a reduction in plasticity, volume change and an increase in the unconfined compressive strength. However, it was observed that the presence of burned olive waste in the soil greater than 3% caused an increase in the compressibility and a decrease in the unconfined compressive strength. Test results indicate that the use of olive waste in soil stabilization gives greater benefits to the environment than simply disposing of the by-product, olive cake residue.

Test Plan to Assess Fire Effects on the Function of an Engineered Surface Barrier

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ward, Anderson L.; Berlin, Gregory T.; Cammann, Jerry W.

2008-09-29

Wildfire is a frequent perturbation in shrub steppe ecosystems, altering the flora, fauna, atmosphere, and soil of these systems. Research on the fire effects has focused mostly on natural ecosystems with essentially no attention on engineered systems like surface barriers. The scope of the project is to use a simulated wildfire to induce changes in an engineered surface barrier and document the effects on barrier performance. The main objective is to quantify the effects of burning and the resulting post-fire conditions on alterations in soil physical properties; hydrologic response, particularly the water balance; geochemical properties; and biological properties. A secondarymore » objective is to use the lessons learned to maximize fire protection in the design of long-term monitoring systems based on electronic sensors. A simulated wildfire will be initiated, controlled and monitored at the 200-BP-1 barrier in collaboration with the Hanford Fire Department during the fall of 2008. The north half of the barrier will be divided into nine 12 x 12 m plots, each of which will be randomly assigned a fuel load of 2 kg m-2 or 4 kg m-2. Each plot will be ignited around the perimeter and flames allowed to carry to the centre. Any remaining unburned vegetation will be manually burned off using a drip torch. Progress of the fire and its effects will be monitored using point measurements of thermal, hydrologic, and biotic variables. Three measures of fire intensity will be used to characterize fire behavior: (1) flame height, (2) the maximum temperature at three vertical profile levels, and (3) total duration of elevated temperature at these levels. Pre-burn plant information, including species diversity, plant height, and canopy diameter will be measured on shrubs from the plots to be burned and from control plots at the McGee ranch. General assessments of shrub survival, recovery, and recruitment will be made after the fire. Near-surface soil samples will be collected pre- and post-burn to determine changes in the gravel content of the surface layer so as to quantify inflationary or deflationary responses to fire and to reveal the ability of the surface to resist post-fire erosive stresses. Measures of bulk density, water repellency, water retention, and hydraulic conductivity will be used to characterize changes in infiltration rates and water storage capacity following the fire. Samples will also be analyzed to quantify geochemical changes including changes in soil pH, cation exchange capacity, specific surface area, and the concentration of macro nutrients (e.g. N, P, K) and other elements such as Na, Mg, Ca, that are critical to the post-fire recovery revegetation. Soil CO2 emissions will be measured monthly for one year following the burn to document post-fire stimulation of carbon turnover and soil biogenic emissions. Surface and subsurface temperature measurements at and near monitoring installations will be used to document fire effects on electronic equipment. The results of this study will be used to bridge the gaps in knowledge on the effects of fire on engineered ecosystems (e.g. surface barriers), particularly the hydrologic and biotic characteristics that govern the water and energy balance. These results will also support the development of practical fire management techniques for barriers that are compatible with wildfire suppression strategies. Furthermore, lessons learned will be use to develop installation strategies needed to protect electronic monitoring equipment from the intense heat of fire and the potential damaging effects of smoke and fire extinguishing agents. Such information is needed to better understand long-term barrier performance under extreme conditions, especially if site maintenance and operational funding is lost for activities such as barrier revegetation.« less

Overview of different aspects of climate change effects on soils

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qafoku, Nikolla P.

2014-08-01

Climate change [i.e., high atmospheric carbon dioxide (CO 2) concentrations (≥400 ppm); increasing air temperatures (2-4°C or greater); significant and/or abrupt changes in daily, seasonal, and inter-annual temperature; changes in the wet/dry cycles; intensive rainfall and/or heavy storms; extended periods of drought; extreme frost; heat waves and increased fire frequency] is and will significantly affect soil properties and fertility, water resources, food quantity and quality, and environmental quality. Biotic processes that consume atmospheric CO 2 and create organic carbon (C) that is either reprocessed to CO 2 or stored in soils, are the subject of active current investigations with greatmore » concern over the influence of climate change. In addition, abiotic C cycling and its influence on the inorganic C pool in soils is a fundamental global process in which acidic atmospheric CO 2 participates in the weathering of carbonate and silicate minerals, ultimately delivering bicarbonate and Ca 2+ or other cations that precipitate in the form of carbonates in soils or are transported to the rivers, lakes, and oceans. Soil responses to climate change will be complex, and there are many uncertainties and unresolved issues. The objective of the review is to initiate and further stimulate a discussion about some important and challenging aspects of climate-change effects on soils, such as accelerated weathering of soil minerals and resulting C and elemental fluxes in and out of soils, soil/geo-engineering methods used to increase C sequestration in soils, soil organic matter (SOM) protection, transformation and mineralization, and SOM temperature sensitivity. This review reports recent discoveries and identifies key research needs required to understand the effects of climate change on soils.« less

Effects of Spatial Variability of Soil Properties on the Triggering of Rainfall-Induced Shallow Landslides

NASA Astrophysics Data System (ADS)

Fan, Linfeng; Lehmann, Peter; Or, Dani

2015-04-01

Naturally-occurring spatial variations in soil properties (e.g., soil depth, moisture, and texture) affect key hydrological processes and potentially the mechanical response of soil to hydromechanical loading (relative to the commonly-assumed uniform soil mantle). We quantified the effects of soil spatial variability on the triggering of rainfall-induced shallow landslides at the hillslope- and catchment-scales, using a physically-based landslide triggering model that considers interacting soil columns with mechanical strength thresholds (represented by the Fiber Bundle Model). The spatial variations in soil properties are represented as Gaussian random distributions and the level of variation is characterized by the coefficient of variation and correlation lengths of soil properties (i.e., soil depth, soil texture and initial water content in this study). The impacts of these spatial variations on landslide triggering characteristics were measured by comparing the times to triggering and landslide volumes for heterogeneous soil properties and homogeneous cases. Results at hillslope scale indicate that for spatial variations of an individual property (without cross correlation), the increasing of coefficient of variation introduces weak spots where mechanical damage is accelerated and leads to earlier onset of landslide triggering and smaller volumes. Increasing spatial correlation length of soil texture and initial water content also induces early landslide triggering and small released volumes due to the transition of failure mode from brittle to ductile failure. In contrast, increasing spatial correlation length of soil depth "reduces" local steepness and postpones landslide triggering. Cross-correlated soil properties generally promote landslide initiation, but depending on the internal structure of spatial distribution of each soil property, landslide triggering may be reduced. The effects of cross-correlation between initial water content and soil texture were investigated in detail at the catchment scale by incorporating correlations of both variables with topography. Results indicate that the internal structure of the spatial distribution of each soil property together with their interplays determine the overall performance of the coupled spatial variability. This study emphasizes the importance of both the randomness and spatial structure of soil properties on landslide triggering and characteristics.

Assimilation of optical and radar remote sensing data in 3D mapping of soil properties over large areas.

PubMed

Poggio, Laura; Gimona, Alessandro

2017-02-01

Soil is very important for many land functions. To achieve sustainability it is important to understand how soils vary over space in the landscape. Remote sensing data can be instrumental in mapping and spatial modelling of soil properties, resources and their variability. The aims of this study were to compare satellite sensors (MODIS, Landsat, Sentinel-1 and Sentinel-2) with varying spatial, temporal and spectral resolutions for Digital Soil Mapping (DSM) of a set of soil properties in Scotland, evaluate the potential benefits of adding Sentinel-1 data to DSM models, select the most suited mix of sensors for DSM to map the considered set of soil properties and validate the results of topsoil (2D) and whole profile (3D) models. The results showed that the use of a mixture of sensors proved more effective to model and map soil properties than single sensors. The use of radar Sentinel-1 data proved useful for all soil properties, improving the prediction capability of models with only optical bands. The use of MODIS time series provided stronger relationships than the use of temporal snapshots. The results showed good validation statistics with a RMSE below 20% of the range for all considered soil properties. The RMSE improved from previous studies including only MODIS sensor and using a coarser prediction grid. The performance of the models was similar to previous studies at regional, national or continental scale. A mix of optical and radar data proved useful to map soil properties along the profile. The produced maps of soil properties describing both lateral and vertical variability, with associated uncertainty, are important for further modelling and management of soil resources and ecosystem services. Coupled with further data the soil properties maps could be used to assess soil functions and therefore conditions and suitability of soils for a range of purposes. Copyright © 2016 Elsevier B.V. All rights reserved.

Application of positive matrix factorization to identify potential sources of PAHs in soil of Dalian, China.

PubMed

Wang, Degao; Tian, Fulin; Yang, Meng; Liu, Chenlin; Li, Yi-Fan

2009-05-01

Soil derived sources of polycyclic aromatic hydrocarbons (PAHs) in the region of Dalian, China were investigated using positive matrix factorization (PMF). Three factors were separated based on PMF for the statistical investigation of the datasets both in summer and winter. These factors were dominated by the pattern of single sources or groups of similar sources, showing seasonal and regional variations. The main sources of PAHs in Dalian soil in summer were the emissions from coal combustion average (46%), diesel engine (30%), and gasoline engine (24%). In winter, the main sources were the emissions from coal-fired boiler (72%), traffic average (20%), and gasoline engine (8%). These factors with strong seasonality indicated that coal combustion in winter and traffic exhaust in summer dominated the sources of PAHs in soil. These results suggested that PMF model was a proper approach to identify the sources of PAHs in soil.

Effect of different soil washing solutions on bioavailability of residual arsenic in soils and soil properties.

PubMed

Im, Jinwoo; Yang, Kyung; Jho, Eun Hea; Nam, Kyoungphile

2015-11-01

The effect of soil washing used for arsenic (As)-contaminated soil remediation on soil properties and bioavailability of residual As in soil is receiving increasing attention due to increasing interest in conserving soil qualities after remediation. This study investigates the effect of different washing solutions on bioavailability of residual As in soils and soil properties after soil washing. Regardless of washing solutions, the sequential extraction revealed that the residual As concentrations and the amount of readily labile As in soils were reduced after soil washing. However, the bioassay tests showed that the washed soils exhibited ecotoxicological effects - lower seed germination, shoot growth, and enzyme activities - and this could largely be attributed to the acidic pH and/or excessive nutrient contents of the washed soils depending on washing solutions. Overall, this study showed that treated soils having lower levels of contaminants could still exhibit toxic effects due to changes in soil properties, which highly depended on washing solutions. This study also emphasizes that data on the As concentrations, the soil properties, and the ecotoxicological effects are necessary to properly manage the washed soils for reuses. The results of this study can, thus, be utilized to select proper post-treatment techniques for the washed soils. Copyright © 2015 Elsevier Ltd. All rights reserved.

JSC-1: A new lunar regolith simulant

NASA Technical Reports Server (NTRS)

Mckay, David S.; Carter, James L.; Boles, Walter W.; Allen, Carlton C.; Allton, Judith H.

1993-01-01

Simulants of lunar rocks and soils with appropriate properties, although difficult to produce in some cases, will be essential to meeting the system requirements for lunar exploration. In order to address this need a new lunar regolith simulant, JSC-1, has been developed. JSC-1 is a glass-rich basaltic ash which approximates the bulk chemical composition and mineralogy of some lunar soils. It has been ground to produce a gain size distribution approximating that of lunar regolith samples. The simulant is available in large quantities (greater than 2000 lb; 907 kg). JSC-1 was produced specifically for large- and medium-scale engineering studies in support of future human activities on the Moon. Such studies include material handling, construction, excavation, and transportation. The simulant is also appropriate for research on dust control and spacesuit durability. JSC-1 can be used as a chemical or mineralogical analog to some lunar soils for resource studies such as oxygen or metal production, sintering, and radiation shielding.

Research on filling scheme and deformation properties of wide subgrade of foamed lightweight soil on soft ground

NASA Astrophysics Data System (ADS)

Zhang, Faru; Yang, Deguang; Zhang, Liujun

2018-01-01

The wide subgrade on soft soil ground has the significantly different transverse settlement curve characteristics and the lacation of the maximum asymmetrical transverse settlement compared with ordinary subgrade. Especially when the subgrade filled with materials of different densities, the synergism deformation of ground-subgrade-pavement and the pavement structure stress become more complex. Combining with the engineering example, the settlement deformation characteristics of wide subgrade adopting the different filling scheme and the stress distribution of pavement structure are analyzed. Results show that the settlement curve of wide subgrade has a shape of flat middle with steep sides, and the maximum transverse asymmetrical settlement locates in close to the shoulder position. The maximum stress within the pavement structure is also in close to the shoulder position. Regarding the wide subgrade composed of main road and relief road, the post-construction settlement can be greatly reduced when both roads are filled with foamed lightweight soil.

Vertical variation of a black soil's properties in response to freeze-thaw cycles and its links to shift of microbial community structure.

PubMed

Han, Ziming; Deng, Mingwen; Yuan, Anqi; Wang, Jiahui; Li, Hao; Ma, Jincai

2018-06-01

Soil freeze-thaw cycles (FTCs) change soil physical, chemical, and biological properties, however information regarding their vertical variations in response to FTCs is limited. In this work, black soil (silty loam) packed soil columns were exposed to 8 FTCs, and soil properties were determined for each of vertical layer of soil columns. The results revealed that after FTCs treatment, moisture and electrical conductivity (EC) salinity tended to increase in upper soil layers. Increments of ammonium nitrogen (NH 4 + -N) and nitrate nitrogen (NO 3 - -N) in top layers (0-10cm) were greater than those in other layers, and increments of water soluble organic carbon (WSOC) and decrease of microbial biomass carbon (MBC) in middle layers (10-20cm) were greater than those in both ends. Overall, microbial community structure was mainly influenced by soil physical properties (moisture and EC) and chemical properties (pH and WSOC). For bacterial (archaeal) and fungal communities, soil physical properties, chemical properties and their interaction explained 79.73% and 82.66% of total variation, respectively. Our results provided insights into the vertical variation of soil properties caused by FTCs, and such variation had a major impact on the change of structure and composition of soil bacterial and fungal communities. Copyright © 2017 Elsevier B.V. All rights reserved.

General Relationships between Abiotic Soil Properties and Soil Biota across Spatial Scales and Different Land-Use Types

PubMed Central

Birkhofer, Klaus; Schöning, Ingo; Alt, Fabian; Herold, Nadine; Klarner, Bernhard; Maraun, Mark; Marhan, Sven; Oelmann, Yvonne; Wubet, Tesfaye; Yurkov, Andrey; Begerow, Dominik; Berner, Doreen; Buscot, François; Daniel, Rolf; Diekötter, Tim; Ehnes, Roswitha B.; Erdmann, Georgia; Fischer, Christiane; Foesel, Bärbel; Groh, Janine; Gutknecht, Jessica; Kandeler, Ellen; Lang, Christa; Lohaus, Gertrud; Meyer, Annabel; Nacke, Heiko; Näther, Astrid; Overmann, Jörg; Polle, Andrea; Pollierer, Melanie M.; Scheu, Stefan; Schloter, Michael; Schulze, Ernst-Detlef; Schulze, Waltraud; Weinert, Jan; Weisser, Wolfgang W.; Wolters, Volkmar; Schrumpf, Marion

2012-01-01

Very few principles have been unraveled that explain the relationship between soil properties and soil biota across large spatial scales and different land-use types. Here, we seek these general relationships using data from 52 differently managed grassland and forest soils in three study regions spanning a latitudinal gradient in Germany. We hypothesize that, after extraction of variation that is explained by location and land-use type, soil properties still explain significant proportions of variation in the abundance and diversity of soil biota. If the relationships between predictors and soil organisms were analyzed individually for each predictor group, soil properties explained the highest amount of variation in soil biota abundance and diversity, followed by land-use type and sampling location. After extraction of variation that originated from location or land-use, abiotic soil properties explained significant amounts of variation in fungal, meso- and macrofauna, but not in yeast or bacterial biomass or diversity. Nitrate or nitrogen concentration and fungal biomass were positively related, but nitrate concentration was negatively related to the abundances of Collembola and mites and to the myriapod species richness across a range of forest and grassland soils. The species richness of earthworms was positively correlated with clay content of soils independent of sample location and land-use type. Our study indicates that after accounting for heterogeneity resulting from large scale differences among sampling locations and land-use types, soil properties still explain significant proportions of variation in fungal and soil fauna abundance or diversity. However, soil biota was also related to processes that act at larger spatial scales and bacteria or soil yeasts only showed weak relationships to soil properties. We therefore argue that more general relationships between soil properties and soil biota can only be derived from future studies that consider larger spatial scales and different land-use types. PMID:22937029

Molecular and Isotopic Analysis of Earthworm Fecal Matter as a Tool for Determining Carbon Cycling Dynamics in two Great Lakes Region Forests

NASA Astrophysics Data System (ADS)

Top, S. M.; Filley, T. R.; Zurn-Birkhimer, S.

2009-12-01

Earthworms are frequently referred to as soil ecosystem engineers, reflecting their role as a potential major factor in controlling the dynamics of litter and soil organic matter transformations. Their significance is magnified when considering they are exotic in northern North American forests, humans acting as the main vector with transport of soil and recreational fishing. As a result of earthworm activity, forests can undergo significant changes to forest floor chemistry and soil structure, possibly increasing nutrient loss from both soil and leaf litter. The impact of earthworms on overall soil carbon stabilization/destabilization is largely unknown but likely a function of both species composition and edaphic soil properties. We are investigating the impacts of exotic earthworms on soils within two Great Lakes region forests; the Aspen free air CO2 enrichment (FACE) site, Rhinelander, WI, and forests in Red Lake Indian Reservation, MN. Aspen FACE provides an opportunity to document the changes that occur to forest chemistry and earthworm activity are a result of increased CO2, while the sites on the Red Lake Reservation are significant because of they contain a gradient of earthworm influence. At both sites earthworm populations were amassed from small pits and isolated to collect gut contents for isotopic and plant biopolymer chemistry analysis. Analysis are ongoing and will eventually include alkaline CuO extraction and isotopic analyses on the fecal matter, leaf litter, and soil to determine how plant biopolymers are vertically transported and mixed with soil from deeper horizons.

Empirical relationship between electrical resistivity and geotechnical parameters: A case study of Federal University of Technology campus, Akure SW, Nigeria

NASA Astrophysics Data System (ADS)

Akintorinwa, O. J.; Oluwole, S. T.

2018-06-01

For several decades, geophysical prospecting method coupled with geotechnical analysis has become increasingly useful in evaluating the subsurface for both pre and post engineering investigations. Shallow geophysical tool is often used alongside geotechnical method to evaluate subsurface soil for engineering study to obtain information which may include the subsurface lithology and their thicknesses, competence of the bedrock and depths to its upper interface, and competence of the material that make up the overburden, especially the shallow section which serves as host for foundations of engineering structures (Aina et al., 1996; Adewumi and Olorunfemi, 2005; and Idornigie et al., 2006). This information helps the engineers to correctly locate and design the foundation of engineering structures. The information also serves as guide to the choice of design and suitable materials needed for road construction (Akinlabi and Adeyemi, 2014). Lack of knowledge of the properties of subsurface may leads to the failure of most engineering structures. Therefore, it is of great importance to carry out a pre-construction investigation of a proposed site in order to ascertain the fitness of the host earth material.

Profile soil property estimation using a VIS-NIR-EC-force probe

USDA-ARS?s Scientific Manuscript database

Combining data collected in-field from multiple soil sensors has the potential to improve the efficiency and accuracy of soil property estimates. Optical diffuse reflectance spectroscopy (DRS) has been used to estimate many important soil properties, such as soil carbon, water content, and texture. ...

A New Non-Destructive TDR System Combined with a Piezoelectric Stack for Measuring Properties of Geomaterials

PubMed Central

Choi, Chanyong; Song, Minwoo; Kim, Daehyeon; Yu, Xiong

2016-01-01

Dry density and water content are two important factors affecting the degree of soil compaction. Conventional methods such as the sand cone test and the plate load test are used to measure such properties for evaluating the degree of compaction and the stiffness of soil in the field. However, these tests are generally very time-consuming and are inherent with some errors depending on the operator (in particular for the sand cone test). Elastic modulus is an indicator to describe the stress-strain behavior of soil and in some cases is used as a design input parameter. Although a rod type TDR (Time Domain Reflectometry) system has been recently proposed to overcome some shortcomings of the conventional methods (particularly the sand cone test), it requires driving the probes into the ground, thus implying that it is still a time-consuming and destructive testing method. This study aims to develop a new non-destructive TDR system that can rapidly measure the dry density, water content, and elastic modulus of soil on the surface of compacted soil, without disturbing the ground. In this study, the Piezoelectric Stack, which is an instrument for measuring the elastic modulus of soil, has been added to the TDR system with a flat type probe, leading to a non-destructive TDR system that is capable of measuring the dry density, water content, and elastic modulus of soil. The new TDR system developed is light enough for an engineer to carry. Results of the standard compaction and TDR tests on sand showed that the dry densities and the moisture contents measured with the new TDR system were in good agreement with those measured with the standard compaction test, respectively. Consequently, it appears that the new TDR system developed will be very useful to advance the current practice of compaction quality control. PMID:28773563

A New Non-Destructive TDR System Combined with a Piezoelectric Stack for Measuring Properties of Geomaterials.

PubMed

Choi, Chanyong; Song, Minwoo; Kim, Daehyeon; Yu, Xiong

2016-06-02

Dry density and water content are two important factors affecting the degree of soil compaction. Conventional methods such as the sand cone test and the plate load test are used to measure such properties for evaluating the degree of compaction and the stiffness of soil in the field. However, these tests are generally very time-consuming and are inherent with some errors depending on the operator (in particular for the sand cone test). Elastic modulus is an indicator to describe the stress-strain behavior of soil and in some cases is used as a design input parameter. Although a rod type TDR (Time Domain Reflectometry) system has been recently proposed to overcome some shortcomings of the conventional methods (particularly the sand cone test), it requires driving the probes into the ground, thus implying that it is still a time-consuming and destructive testing method. This study aims to develop a new non-destructive TDR system that can rapidly measure the dry density, water content, and elastic modulus of soil on the surface of compacted soil, without disturbing the ground. In this study, the Piezoelectric Stack, which is an instrument for measuring the elastic modulus of soil, has been added to the TDR system with a flat type probe, leading to a non-destructive TDR system that is capable of measuring the dry density, water content, and elastic modulus of soil. The new TDR system developed is light enough for an engineer to carry. Results of the standard compaction and TDR tests on sand showed that the dry densities and the moisture contents measured with the new TDR system were in good agreement with those measured with the standard compaction test, respectively. Consequently, it appears that the new TDR system developed will be very useful to advance the current practice of compaction quality control.

Biochar: from laboratory mechanisms through the greenhouse to field trials

NASA Astrophysics Data System (ADS)

Masiello, C. A.; Gao, X.; Dugan, B.; Silberg, J. J.; Zygourakis, K.; Alvarez, P. J. J.

2014-12-01

The biochar community is excellent at pointing to individual cases where biochar amendment has changed soil properties, with some studies showing significant improvements in crop yields, reduction in nutrient export, and remediation of pollutants. However, many studies exist which do not show improvements, and in some cases, studies clearly show detrimental outcomes. The next, crucial step in biochar science and engineering research will be to develop a process-based understanding of how biochar acts to improve soil properties. In particular, we need a better mechanistic understanding of how biochar sorbs and desorbs contaminants, how it interacts with soil water, and how it interacts with the soil microbial community. These mechanistic studies need to encompass processes that range from the nanometer to the kilometer scale. At the nanometer scale, we need a predictive model of how biochar will sorb and desorb hydrocarbons, nutrients, and toxic metals. At the micrometer scale we need models that explain biochar's effects on soil water, especially the plant-available fraction of soil water. The micrometer scale is also where mechanistic information is neeed about microbial processes. At the macroscale we need physical models to describe the landscape mobility of biochar, because biochar that washes away from fields can no longer provide crop benefits. To be most informative, biochar research should occur along a lab-greenhouse-field trial trajectory. Laboratory experiments should aim determine what mechanisms may act to control biochar-soil processes, and then greenhouse experiments can be used to test the significance of lab-derived mechanisms in short, highly replicated, controlled experiments. Once evidence of effect is determined from greenhouse experiments, field trials are merited. Field trials are the gold standard needed prior to full deployment, but results from field trials cannot be extrapolated to other field sites without the mechanistic backup provided by greenhouse and lab trials.

Influence of thinning Loblolly Pine (Pinus taeda L.) on hydraulic properties of an organic soil

Treesearch

Johnny M. Grace; R. W. Skaggs; D. Keith Cassel

2006-01-01

The impact of forest operations on soil properties has been a concern in forest management over the past 30 years. The objective of this study was to evaluate the impact of forest thinning operations on soil hydraulic properties of a shallow organic (Belhaven series) soil in the Tidewater region of North Carolina. Soil physical properties were evaluated in a nested...

Wetland eco-engineering: measuring and modeling feedbacks of oxidation processes between plants and clay-rich material

NASA Astrophysics Data System (ADS)

Saaltink, Rémon; Dekker, Stefan C.; Griffioen, Jasper; Wassen, Martin J.

2016-09-01

Interest is growing in using soft sediment as a foundation in eco-engineering projects. Wetland construction in the Dutch lake Markermeer is an example: here, dredging some of the clay-rich lake-bed sediment and using it to construct wetland will soon begin. Natural processes will be utilized during and after construction to accelerate ecosystem development. Knowing that plants can eco-engineer their environment via positive or negative biogeochemical plant-soil feedbacks, we conducted a 6-month greenhouse experiment to identify the key biogeochemical processes in the mud when Phragmites australis is used as an eco-engineering species. We applied inverse biogeochemical modeling to link observed changes in pore water composition to biogeochemical processes. Two months after transplantation we observed reduced plant growth and shriveling and yellowing of foliage. The N : P ratios of the plant tissue were low, and these were affected not by hampered uptake of N but by enhanced uptake of P. Subsequent analyses revealed high Fe concentrations in the leaves and roots. Sulfate concentrations rose drastically in our experiment due to pyrite oxidation; as reduction of sulfate will decouple Fe-P in reducing conditions, we argue that plant-induced iron toxicity hampered plant growth, forming a negative feedback loop, while simultaneously there was a positive feedback loop, as iron toxicity promotes P mobilization as a result of reduced conditions through root death, thereby stimulating plant growth and regeneration. Given these two feedback mechanisms, we propose the use of Fe-tolerant species rather than species that thrive in N-limited conditions. The results presented in this study demonstrate the importance of studying the biogeochemical properties of the situated sediment and the feedback mechanisms between plant and soil prior to finalizing the design of the eco-engineering project.

Geotechnical Engineering in US Elementary Schools

ERIC Educational Resources Information Center

Suescun-Florez, Eduardo; Iskander, Magued; Kapila, Vikram; Cain, Ryan

2013-01-01

This paper reports on the results of several geotechnical engineering-related science activities conducted with elementary-school students. Activities presented include soil permeability, contact stress, soil stratigraphy, shallow and deep foundations, and erosion in rivers. The permeability activity employed the LEGO NXT platform for data…

ONSITE ENGINEERING REPORT FOR SOLIDIFICATION/ STABILIZATION TREATMENT TESTING OF CONTAMINATED SOILS

EPA Science Inventory

The EPA's Office of Solid Waste and Emergency Response (OSWER) is currently developing land disposal restrictions (LDRs) for contaminated soil and debris (CS&D). The Office of Research and Development, through its Risk Reduction Engineering Laboratory (RREL), is providing support...

A Biogeotechnical approach to Stabilize Soft Marine Soil with a Microbial Organic Material called Biopolymer

NASA Astrophysics Data System (ADS)

Chang, I.; Cho, G. C.; Kwon, Y. M.; Im, J.

2017-12-01

The importance and demands of offshore and coastal area development are increasing due to shortage of usable land and to have access to valuable marine resources. However, most coastal soils are soft sediments, mainly composed with fines (silt and clay) and having high water and organic contents, which induce complicated mechanical- and geochemical- behaviors and even be insufficient in Geotechnical engineering aspects. At least, soil stabilization procedures are required for those soft sediments, regardless of the purpose of usage on the site. One of the most common soft soil stabilization method is using ordinary cement as a soil strengthening binder. However, the use of cement in marine environments is reported to occur environmental concerns such as pH increase and accompanying marine ecosystem disturbance. Therefore, a new environmentally-friendly treatment material for coastal and offshore soils. In this study, a biopolymer material produced by microbes is introduced to enhance the physical behavior of a soft tidal flat sediment by considering the biopolymer rheology, soil mineralogy, and chemical properties of marine water. Biopolymer material used in this study forms inter-particle bonds between particles which is promoted through cation-bridges where the cations are provided from marine water. Moreover, biopolymer treatment renders unique stress-strain relationship of soft soils. The mechanical stiffness (M) instantly increase with the presence of biopolymer, while time-dependent settlement behavior (consolidation) shows a big delay due to the viscous biopolymer hydrogels in pore spaces.

Combining local scaling and global methods to detect soil pore space

NASA Astrophysics Data System (ADS)

Martin-Sotoca, Juan Jose; Saa-Requejo, Antonio; Grau, Juan B.; Tarquis, Ana M.

2017-04-01

The characterization of the spatial distribution of soil pore structures is essential to obtain different parameters that will influence in several models related to water flow and/or microbial growth processes. The first step in pore structure characterization is obtaining soil images that best approximate reality. Over the last decade, major technological advances in X-ray computed tomography (CT) have allowed for the investigation and reconstruction of natural porous media architectures at very fine scales. The subsequent step is delimiting the pore structure (pore space) from the CT soil images applying a thresholding. Many times we could find CT-scan images that show low contrast at the solid-void interface that difficult this step. Different delimitation methods can result in different spatial distributions of pores influencing the parameters used in the models. Recently, new local segmentation method using local greyscale value (GV) concentration variabilities, based on fractal concepts, has been presented. This method creates singularity maps to measure the GV concentration at each point. The C-A method was combined with the singularity map approach (Singularity-CA method) to define local thresholds that can be applied to binarize CT images. Comparing this method with classical methods, such as Otsu and Maximum Entropy, we observed that more pores can be detected mainly due to its ability to amplify anomalous concentrations. However, it delineated many small pores that were incorrect. In this work, we present an improve version of Singularity-CA method that avoid this problem basically combining it with the global classical methods. References Martín-Sotoca, J.J., A. Saa-Requejo, J.B. Grau, A.M. Tarquis. New segmentation method based on fractal properties using singularity maps. Geoderma, 287, 40-53, 2017. Martín-Sotoca, J.J, A. Saa-Requejo, J.B. Grau, A.M. Tarquis. Local 3D segmentation of soil pore space based on fractal properties using singularity maps. Geoderma, http://dx.doi.org/10.1016/j.geoderma.2016.11.029. Torre, Iván G., Juan C. Losada and A.M. Tarquis. Multiscaling properties of soil images. Biosystems Engineering, http://dx.doi.org/10.1016/j.biosystemseng.2016.11.006.

Disentangling above- and below-ground facilitation drivers in arid environments: the role of soil microorganisms, soil properties and microhabitat.

PubMed

Lozano, Yudi M; Armas, Cristina; Hortal, Sara; Casanoves, Fernando; Pugnaire, Francisco I

2017-12-01

Nurse plants promote establishment of other plant species by buffering climate extremes and improving soil properties. Soil biota plays an important role, but an analysis to disentangle the effects of soil microorganisms, soil properties and microclimate on facilitation is lacking. In three microhabitats (gaps, small and large Retama shrubs), we placed six microcosms with sterilized soil, two per soil origin (i.e. from each microhabitat). One in every pair received an alive, and the other a sterile, inoculum from its own soil. Seeds of annual plants were sown into the microcosms. Germination, survival and biomass were monitored. Soil bacterial communities were characterized by pyrosequencing. Germination in living Retama inoculum was nearly double that of germination in sterile inoculum. Germination was greater under Retama canopies than in gaps. Biomass was up to three times higher in nurse than in gap soils. Soil microorganisms, soil properties and microclimate showed a range of positive to negative effects on understory plants depending on species identity and life stage. Nurse soil microorganisms promoted germination, but the effect was smaller than the positive effects of soil properties and microclimate under nurses. Nurse below-ground environment (soil properties and microorganisms) promoted plant growth and survival more than nurse microhabitat. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

Comparison of field and laboratory VNIR spectroscopy for profile soil property estimation

USDA-ARS?s Scientific Manuscript database

In-field, in-situ data collection with soil sensors has potential to improve the efficiency and accuracy of soil property estimates. Optical diffuse reflectance spectroscopy (DRS) has been used to estimate important soil properties, such as soil carbon, nitrogen, water content, and texture. Most pre...

Estimation of soil profile physical and chemical properties using a VIS-NIR-EC-force probe

USDA-ARS?s Scientific Manuscript database

Combining data collected in-field from multiple soil sensors has the potential to improve the efficiency and accuracy of soil property estimates. Optical diffuse reflectance spectroscopy (DRS) has been used to estimate many important soil properties, such as soil carbon, water content, and texture. ...

ENGINEERING BULLETIN: IN SITU SOIL FLUSHING

EPA Science Inventory

In situ soil flushing is the extraction of contaminants from the soil with water or other suitable aqueous solutions. Soil flushing is accomplished by passing the extraction fluid through in-place soils using an injection or infiltration process. Extraction fluids must be recover...

Effects of Biochar Amendment on Soil Properties and Soil Carbon Sequestration

NASA Astrophysics Data System (ADS)

Zhang, R.; Zhu, S.

2015-12-01

Biochar addition to soils potentially affects various soil properties and soil carbon sequestration, and these effects are dependent on biochars derived from different feedstock materials and pyrolysis processes. The objective of this study was to investigate the effects of amendment of different biochars on soil physical and biological properties as well as soil carbon sequestration. Biochars were produced with dairy manure and woodchip at temperatures of 300, 500, and 700°C, respectively. Each biochar was mixed at 5% (w/w) with a forest soil and the mixture was incubated for 180 days, during which soil physical and biological properties, and soil respiration rates were measured. Results showed that the biochar addition significantly enhanced the formation of soil macroaggregates at the early incubation time. The biochar application significantly reduced soil bulk density, increased the amount of soil organic matter, and stimulated microbial activity and soil respiration rates at the early incubation stage. Biochar applications improved water retention capacity, with stronger effects by biochars produced at higher pyrolysis temperatures. At the same suction, the soil with woodchip biochars possessed higher water content than with the dairy manure biochars. Biochar addition significantly affected the soil physical and biological properties, which resulted in different soil carbon mineralization rates and the amount of soil carbon storage.

Relationships between basic soils-engineering equations and basic ground-water flow equations

USGS Publications Warehouse

Jorgensen, Donald G.

1980-01-01

The many varied though related terms developed by ground-water hydrologists and by soils engineers are useful to each discipline, but their differences in terminology hinder the use of related information in interdisciplinary studies. Equations for the Terzaghi theory of consolidation and equations for ground-water flow are identical under specific conditions. A combination of the two sets of equations relates porosity to void ratio and relates the modulus of elasticity to the coefficient of compressibility, coefficient of volume compressibility, compression index, coefficient of consolidation, specific storage, and ultimate compaction. Also, transient ground-water flow is related to coefficient of consolidation, rate of soil compaction, and hydraulic conductivity. Examples show that soils-engineering data and concepts are useful to solution of problems in ground-water hydrology.

Field Soil Water Retention of the Prototype Hanford Barrier and Its Variability with Space and Time

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Z. F.

Engineered surface barriers are used to isolate underlying contaminants from water, plants, animals, and humans. To understand the flow processes within a barrier and the barrier’s ability to store and release water, the field hydraulic properties of the barrier need to be known. In situ measurement of soil hydraulic properties and their variation over time is challenging because most measurement methods are destructive. A multiyear test of the Prototype Hanford Barrier (PHB) has yielded in situ soil water content and pressure data for a nine-year period. The upper 2 m layer of the PHB is a silt loam. Within thismore » layer, water content and water pressure were monitored at multiple depths at 12 water balance stations using a neutron probe and heat dissipation units. Valid monitoring data from 1995 to 2003 for 4 depths at 12 monitoring stations were used to determine the field water retention of the silt loam layer. The data covered a wide range of wetness, from near saturation to the permanent wilt point, and each retention curve contained 51 to 96 data points. The data were described well with the commonly used van Genuchten water retention model. It was found that the spatial variation of the saturated and residual water content and the pore size distribution parameter were relatively small, while that of the van Genuchten alpha was relatively large. The effects of spatial variability of the retention properties appeared to be larger than the combined effects of added 15% w/w pea gravel and plant roots on the properties. Neither of the primary hydrological processes nor time had a detectible effect on the water retention of the silt loam barrier.« less

ENGINEERING ISSUE: TECHNOLOGY ALTERNATIVES FOR THE REMEDIATION OF PCB-CONTAMINATED SOIL AND SEDIMENT

EPA Science Inventory

Because of the increased need for Superfund decision-makers to have a working knowledge of the remedial capabilities available to treat soil and sediment contaminated with polychlorinated biphenyls (PCBs), the Superfund Engineering Forum has identified remediation of PCB-contamin...

Nanoscale interactions between engineered nanomaterials and black carbon (Biochar) in soil

USDA-ARS?s Scientific Manuscript database

Engineered nanomaterials (NMs) enter agricultural soils directly as additives in agrichemical formulations1 and indirectly as contaminants in municipal sewage sludge.2 NIFA has a vested interest in developing predictive models for the fate and nanotoxicity of NMs in agroecosystems. An understanding ...

Determination of field-effective soil properties in the tidewater region of North Carolina

Treesearch

J. McFero Grace; R.W. Skaggs

2013-01-01

Soils vary spatially in texture, structure, depth of horizons, and macropores, which can lead to a large variation in soil physical properties. In particular, saturated hydraulic conductivity (Ksat) and drainable porosity are critical properties required to model field hydrology in poorly drained lands. These soil-property values can be measured...

Soil microbiological properties and enzymatic activities of long-term post-fire recovery in dry and semiarid Aleppo pine (Pinus halepensis M.) forest stands

NASA Astrophysics Data System (ADS)

Hedo, J.; Lucas-Borja, M. E.; Wic, C.; Andrés-Abellán, M.; de Las Heras, J.

2015-02-01

Wildfires affecting forest ecosystems and post-fire silvicultural treatments may cause considerable changes in soil properties. The capacity of different microbial groups to recolonise soil after disturbances is crucial for proper soil functioning. The aim of this work was to investigate some microbial soil properties and enzyme activities in semiarid and dry Aleppo pine (Pinus halepensis M.) forest stands. Different plots affected by a wildfire event 17 years ago without or with post-fire silvicultural treatments 5 years after the fire event were selected. A mature Aleppo pine stand, unaffected by wildfire and not thinned was used as a control. Physicochemical soil properties (soil texture, pH, carbonates, organic matter, electrical conductivity, total N and P), soil enzymes (urease, phosphatase, β-glucosidase and dehydrogenase activities), soil respiration and soil microbial biomass carbon were analysed in the selected forests areas and plots. The main finding was that long time after this fire event produces no differences in the microbiological soil properties and enzyme activities of soil after comparing burned and thinned, burned and not thinned, and mature plots. Moreover, significant site variation was generally seen in soil enzyme activities and microbiological parameters. We conclude that total vegetation recovery normalises post-fire soil microbial parameters, and that wildfire and post-fire silvicultural treatments are not significant factors affecting soil properties after 17 years.

Above the weathering front: contrasting approaches to the study and classification of weathered mantle

NASA Astrophysics Data System (ADS)

Ehlen, Judy

2005-04-01

Weathered mantle comprises the materials above bedrock and below the soil. It can vary in thickness from millimeters to hundreds of meters, depending primarily on climate and parent material. Study of the weathered mantle comes within the realms of four disciplines: geology, geomorphology, soil science, and civil engineering, each of which uses a different approach to describe and classify the material. The approaches of engineers, geomorphologists, and geologists are contrasted and compared using example papers from the published literature. Soil scientists rarely study the weathering profile as such, and instead concentrate upon soil-forming processes and spatial distribution primarily in the solum. Engineers, including engineering geologists, study the stability and durability of the weathered mantle and the strength of the materials using sophisticated procedures to classify weathered materials, but their approach tends to be one-dimensional. Furthermore, they believe that the study of mineralogy and chemistry is not useful. Geomorphologists deal with weathering in terms of process—how the weathered mantle is formed—and with respect to landform evolution using a spatial approach. Geologists tend to ignore the weathered mantle because it is not bedrock, or to study its mineralogy and/or chemistry in the laboratory. I recommend that the approaches of the various disciplines be integrated—geomorphologists and geologists should consider using engineering weathering classifications, and geologists should adopt a spatial perspective to weathering, as should engineers and engineering geologists.

Calibrating Nonlinear Soil Material Properties for Seismic Analysis Using Soil Material Properties Intended for Linear Analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Spears, Robert Edward; Coleman, Justin Leigh

2015-08-01

Seismic analysis of nuclear structures is routinely performed using guidance provided in “Seismic Analysis of Safety-Related Nuclear Structures and Commentary (ASCE 4, 1998).” This document, which is currently under revision, provides detailed guidance on linear seismic soil-structure-interaction (SSI) analysis of nuclear structures. To accommodate the linear analysis, soil material properties are typically developed as shear modulus and damping ratio versus cyclic shear strain amplitude. A new Appendix in ASCE 4-2014 (draft) is being added to provide guidance for nonlinear time domain SSI analysis. To accommodate the nonlinear analysis, a more appropriate form of the soil material properties includes shear stressmore » and energy absorbed per cycle versus shear strain. Ideally, nonlinear soil model material properties would be established with soil testing appropriate for the nonlinear constitutive model being used. However, much of the soil testing done for SSI analysis is performed for use with linear analysis techniques. Consequently, a method is described in this paper that uses soil test data intended for linear analysis to develop nonlinear soil material properties. To produce nonlinear material properties that are equivalent to the linear material properties, the linear and nonlinear model hysteresis loops are considered. For equivalent material properties, the shear stress at peak shear strain and energy absorbed per cycle should match when comparing the linear and nonlinear model hysteresis loops. Consequently, nonlinear material properties are selected based on these criteria.« less

Soil structural quality assessment for soil protection regulation

NASA Astrophysics Data System (ADS)

Johannes, Alice; Boivin, Pascal

2017-04-01

Soil quality assessment is rapidly developing worldwide, though mostly focused on the monitoring of arable land and soil fertility. Soil protection regulations assess soil quality differently, focusing on priority pollutants and threshold values. The soil physical properties are weakly considered, due to lack of consensus and experimental difficulties faced with characterization. Non-disputable, easy to perform and inexpensive methods should be available for environmental regulation to be applied, which is unfortunately not the case. As a consequence, quantitative soil physical protection regulation is not applied, and inexpensive soil physical quality indicators for arable soil management are not available. Overcoming these limitations was the objective of a research project funded by the Swiss federal office for environment (FOEN). The main results and the perspectives of application are given in this presentation. A first step of the research was to characterize soils in a good structural state (reference soils) under different land use. The structural quality was assessed with field expertise and Visual Evaluation of the Soil Structure (VESS), and the physical properties were assessed with Shrinkage analysis. The relationships between the physical properties and the soil constituents were linear and highly determined. They represent the reference properties of the corresponding soils. In a second step, the properties of physically degraded soils were analysed and compared to the reference properties. This allowed defining the most discriminant parameters departing the different structure qualities and their threshold limits. Equivalent properties corresponding to these parameters but inexpensive and easy to determine were defined and tested. More than 90% of the samples were correctly classed with this method, which meets, therefore, the requirements for practical application in regulation. Moreover, result-oriented agri-environmental schemes for soil quality are now proposed to farmers based on these indicators.

A Brief History of the use of Electromagnetic Induction Techniques in Soil Survey

NASA Astrophysics Data System (ADS)

Brevik, Eric C.; Doolittle, James

2017-04-01

Electromagnetic induction (EMI) has been used to characterize the spatial variability of soil properties since the late 1970s. Initially used to assess soil salinity, the use of EMI in soil studies has expanded to include: mapping soil types; characterizing soil water content and flow patterns; assessing variations in soil texture, compaction, organic matter content, and pH; and determining the depth to subsurface horizons, stratigraphic layers or bedrock, among other uses. In all cases the soil property being investigated must influence soil apparent electrical conductivity (ECa) either directly or indirectly for EMI techniques to be effective. An increasing number and diversity of EMI sensors have been developed in response to users' needs and the availability of allied technologies, which have greatly improved the functionality of these tools and increased the amount and types of data that can be gathered with a single pass. EMI investigations provide several benefits for soil studies. The large amount of georeferenced data that can be rapidly and inexpensively collected with EMI provides more complete characterization of the spatial variations in soil properties than traditional sampling techniques. In addition, compared to traditional soil survey methods, EMI can more effectively characterize diffuse soil boundaries and identify included areas of dissimilar soils within mapped soil units, giving soil scientists greater confidence when collecting spatial soil information. EMI techniques do have limitations; results are site-specific and can vary depending on the complex interactions among multiple and variable soil properties. Despite this, EMI techniques are increasingly being used to investigate the spatial variability of soil properties at field and landscape scales. The future should witness a greater use of multiple-frequency and multiple-coil EMI sensors and integration with other sensors to assess the spatial variability of soil properties. Data analysis will be improved with advanced processing and presentation systems and more sophisticated geostatistical modeling algorithms will be developed and used to interpolate EMI data, improve the resolution of subsurface features, and assess soil properties.

Physically-based failure analysis of shallow layered soil deposits over large areas

NASA Astrophysics Data System (ADS)

Cuomo, Sabatino; Castorino, Giuseppe Claudio; Iervolino, Aniello

2014-05-01

In the last decades, the analysis of slope stability conditions over large areas has become popular among scientists and practitioners (Cascini et al., 2011; Cuomo and Della Sala, 2013). This is due to the availability of new computational tools (Baum et al., 2002; Godt et al., 2008; Baum and Godt, 2012; Salciarini et al., 2012) - implemented in GIS (Geographic Information System) platforms - which allow taking into account the major hydraulic and mechanical issues related to slope failure, even for unsaturated soils, as well as the spatial variability of both topography and soil properties. However, the effectiveness (Sorbino et al., 2010) of the above methods it is still controversial for landslides forecasting especially depending on the accuracy of DTM (Digital Terrain Model) and for the chance that distinct triggering mechanisms may occur over large area. Among the major uncertainties, layering of soil deposits is of primary importance due to soil layer conductivity contrast and differences in shear strength. This work deals with the hazard analysis of shallow landslides over large areas, considering two distinct schematizations of soil stratigraphy, i.e. homogeneous or layered. To this purpose, the physically-based model TRIGRS (Baum et al., 2002) is firstly used, then extended to the case of layered deposit: specifically, a unique set of hydraulic properties is assumed while distinct soil unit weight and shear strength are considered for each soil layer. Both models are applied to a significant study area of Southern Italy, about 4 km2 large, where shallow deposits of air-fall volcanic (pyroclastic) soils have been affected by several landslides, causing victims, damages and economic losses. The achieved results highlight that soil volume globally mobilized over the study area highly depends on local stratigraphy of shallow deposits. This relates to the depth of critical slip surface which rarely corresponds to the bedrock contact where cohesionless coarse materials lie on deeper soil layers with small effective cohesion. It is also shown that, due to a more realistic assessment of soil stratigraphy, the success of the model may increase when performing a back-analysis of a recent real event. References Baum, R. L., W. Z. Savage, and J. W. Godt (2002), TRIGRS-A Fortran program for transient rainfall infiltration and grid-based regional slope-stability analysis. U.S. Geological Survey, Open-file report 02-424, 35 p. Baum, R.L., Godt, J.W. (2012) Assessment of shallow landslide potential using 1-D and 3-D slope stability analysis Landslides and Engineered Slopes: Protecting Society through Improved Understanding - Eberhardt et al. (eds) 2012 Taylor & Francis Group, London, ISBN 978-0-415-62123-6, 1667-1672. Cascini L., Cuomo S., Della Sala M. (2011). Spatial and temporal occurrence of rainfall-induced shallow landslides of flow type: A case of Sarno-Quindici, Italy. Geomorphology, 126(1-2), 148-158. Cuomo S., Della Sala M. (2013). Spatially distributed analysis of shallow landslides and soil erosion induced by rainfall. (submitted to Natural Hazards). Godt, J.W., Baum, R.L., Savage, W.Z., Salciarini, D., Schulz, W.H., Harp, E.L. (2008). Transient deterministic shallow landslide modeling: requirements for susceptibility and hazard assessments in a GIS framework. Engineering Geology 102, 214-226. Salciarini, D., Tamagnini, C., Conversini, P., Rapinesi, S. (2012). Spatially distributed rainfall thresholds for the initiation of shallow landslides. Natural Hazards 61, 229-245. Sorbino G., Sica C., Cascini L. (2010). Susceptibility analysis of shallow landslides source areas using physically based models. Natural Hazards, 53(2), 313-332.

Land management on soil physical properties and maize (Zea mays L. var. BIMA) growth (An adaptation strategy of climate change)

NASA Astrophysics Data System (ADS)

Zaki, M. K.; Komariah; Pujiasmanto, B.; Noda, K.

2018-03-01

Water deficit is a problem on rainfed maize production but can be solved by proper land management. The objective of the study to determine the soil physical properties and maize yield affected by land management to adapt to drought. The experimental design was a randomized complete block using 5 treatments with 4 repetitions, including: (i) Control (KO), (ii) Rice Straw Mulched (MC), (iii) Compost Fertilizer (CF), (iv) In-Organic Fertilizer (AF), (v) Legume Cover crop (CC). Soil physical and maize growth properties namely soil moisture, soil texture, soil bulk density, plant height, biomass, and yield were investigated. The results showed that composting land increased soil water availability and provided nutrient to crops and thus increase soil physical properties, maize growth and yield. Although inorganic fertilizer also increased plant growth and yield, but it did not improve soil physical properties.

Contribution of ants in modifying of soil acidity and particle size distribution

NASA Astrophysics Data System (ADS)

Morgun, Alexandra; Golichenkov, Maxim

2015-04-01

Being a natural body, formed by the influence of biota on the upper layers of the Earth's crust, the soil is the most striking example of biogenic-abiogenic interactions in the biosphere. Invertebrates (especially ants that build soil nests) are important agents that change soil properties in well developed terrestrial ecosystems. Impact of soil microorganisms on soil properties is particularly described in numerous literature and concerns mainly chemical properties and general indicators of soil biological activity. Influence of ants (as representatives of the soil mesofauna) mostly appears as mechanical movement of soil particles and aggregates, and chemical effects caused by concentration of organic matter within the ant's nest. The aim of this research was to evaluate the effect of ants on physical and chemical soil attributes such as particle size distribution and soil acidity. The samples were taken from aerial parts of Lasius niger nests, selected on different elements of the relief (summit position, slope, terrace and floodplain) in the Arkhangelsk region (north of the European part of Russia) and compared with the specimens of the upper horizons of the reference soils. Particle size distribution was determined by laser diffraction method using laser diffraction particle size analyzer «Analysette 22 comfort» (FRITSCH, Germany). The acidity (pH) was determined by potentiometry in water suspension. Particle size distribution of the samples from the nests is more variable as compared to the control samples. For example, the content of 5-10 μm fraction ranges from 9% to 12% in reference soils, while in the anthill samples the variation is from 8% to 15%. Similarly, for 50-250 μm fraction - it ranges from 15% to 18% in reference soils, whereas in anthills - from 6% to 29%. The results of particle size analysis showed that the reference sample on the terrace has silty loam texture and nests soil L. niger are medium loam. The reference soil on the slope is characterized as medium loam, and ant's nest material has silty loam texture. The control samples of soil and ants nests on the summit position are similar and have medium loam texture. Generally we outline that the particle size distribution of anthill samples shows more variability. We assume that ants operate with small soil aggregates, in which fine fractions may link together coarser particles. pH measurements show that the reference soils have a strongly acidic reaction on the summit position (pH 4.6), slightly acidic on the slope (pH 5.5) and neutral on the terrace and on the floodplain (pH 7.2). While the material of the anthills tends to be slightly alkalinized on the summit (pH 4.8) and alkalinized on the slope (pH 7.2), but acidified to neutral on the floodplain and terrace (pH 6.4 and 5.7). Therefore, the ants form specific physico-chemical conditions that are different from the surrounding (native) soil, significantly increasing the complexity of soil cover structure. This is a clear example of ecosystem engineering functions of ants in nature. Increased complexity of soil pattern is the result of variations in pH and particle size distribution. Both cause the preconditions for the formation of new environmental niches and enhance biodiversity in natural ecosystems.

Effects of amendment of different biochars on soil physical and biological properties related to carbon mineralization

NASA Astrophysics Data System (ADS)

Zhang, Renduo; Zhu, Shuzhi; Ouyang, Lei

2014-05-01

Biochar addition to soils potentially affects various soil properties, and these effects are dependent on biochars derived from different feedstock materials and pyrolysis processes. The objective of this study was to investigate the effects of amendment of different biochars on soil physical and biological properties. Biochars were produced with dairy manure and woodchip at temperatures of 300, 500, and 700°C, respectively. Each biochar was mixed at 5% (w/w) with a forest soil and the mixture was incubated for 180 days, during which soil physical and biological properties, and soil respiration rates were measured. Results showed that the biochar addition significantly enhanced the formation of soil macroaggregates at the early incubation time. The biochar application significantly reduced soil bulk density, increased the amount of soil organic matter, and stimulated microbial activity and soil respiration rates at the early incubation stage. Biochar applications improved water retention capacity, with stronger effects by biochars produced at higher pyrolysis temperatures. At the same suction, the soil with woodchip biochars possessed higher water content than with the dairy manure biochars. Biochar addition significantly affected the soil physical and biological properties, which resulted in different soil carbon mineralization rates.

A quantitative index of soil development from field descriptions: Examples from a chronosequence in central California

USGS Publications Warehouse

Harden, J.W.

1982-01-01

A soil development index has been developed in order to quantitatively measure the degree of soil profile development. This index, which combines eight soil field properties with soil thickness, is designed from field descriptions of the Merced River chronosequence in central California. These eight properties are: clay films, texture plus wet consistence, rubification (color hue and chroma), structure, dry consistence, moist consistence, color value, and pH. Other properties described in the field can be added when more soils are studied. Most of the properties change systematically within the 3 m.y. age span of the Merced River chronosequence. The absence of properties on occasion does not significantly affect the index. Individual quantified field properties, as well as the integrated index, are examined and compared as functions of soil depth and age. ?? 1982.

Technology-Driven and Innovative Training for Sustainable Agriculture in The Face of Climate Change

NASA Astrophysics Data System (ADS)

Wishart, D. N.

2015-12-01

Innovative training in 'Sustainable Agriculture' for an increasingly STEM-dependent agricultural sector will require a combination of approaches and technologies for global agricultural production to increase while offsetting climate change. Climate change impacts the water resources of nations as normal global weather patterns are altered during El Nino events. Agricultural curricula must incorporate awareness of 'climate change' in order to find novel ways to (1) assure global food security; (2) improve soil productivity and conservation; (3) improve crop yields and irrigation; (4) inexpensively develop site specific principles of crop management based on variable soil and associated hydrological properties; and (5) improve precision farming. In February 2015, Central State University (CSU), Ohio became an 1890 Land-Grant institution vital to the sustainability of Ohio's agricultural sector. Besides agricultural extension, the agriculture curriculum at CSU integrates multidisciplinary courses in science, technology engineering, agriculture, and mathematics (STEAM). The agriculture program could benefit from a technology-driven, interdisciplinary soil science course that promotes climate change education and climate literacy while being offered in both a blended and collaborative learning environment. The course will focus on the dynamics of microscale to mesoscale processes occurring in farming systems, those of which impact climate change or could be impacted by climate change. Elements of this course will include: climate change webinars; soil-climate interactions; carbon cycling; the balance of carbon fluxes between soil storage and atmosphere; microorganisms and soil carbon storage; paleoclimate and soil forming processes; geophysical techniques used in the characterization of soil horizons; impact of climate change on soil fertility; experiments; and demonstrations.

Soil organic carbon dynamics jointly controlled by climate, carbon inputs, soil properties and soil carbon fractions.

PubMed

Luo, Zhongkui; Feng, Wenting; Luo, Yiqi; Baldock, Jeff; Wang, Enli

2017-10-01

Soil organic carbon (SOC) dynamics are regulated by the complex interplay of climatic, edaphic and biotic conditions. However, the interrelation of SOC and these drivers and their potential connection networks are rarely assessed quantitatively. Using observations of SOC dynamics with detailed soil properties from 90 field trials at 28 sites under different agroecosystems across the Australian cropping regions, we investigated the direct and indirect effects of climate, soil properties, carbon (C) inputs and soil C pools (a total of 17 variables) on SOC change rate (r C , Mg C ha -1  yr -1 ). Among these variables, we found that the most influential variables on r C were the average C input amount and annual precipitation, and the total SOC stock at the beginning of the trials. Overall, C inputs (including C input amount and pasture frequency in the crop rotation system) accounted for 27% of the relative influence on r C , followed by climate 25% (including precipitation and temperature), soil C pools 24% (including pool size and composition) and soil properties (such as cation exchange capacity, clay content, bulk density) 24%. Path analysis identified a network of intercorrelations of climate, soil properties, C inputs and soil C pools in determining r C . The direct correlation of r C with climate was significantly weakened if removing the effects of soil properties and C pools, and vice versa. These results reveal the relative importance of climate, soil properties, C inputs and C pools and their complex interconnections in regulating SOC dynamics. Ignorance of the impact of changes in soil properties, C pool composition and C input (quantity and quality) on SOC dynamics is likely one of the main sources of uncertainty in SOC predictions from the process-based SOC models. © 2017 John Wiley & Sons Ltd.

Bacterial community structure and soil properties of a subarctic tundra soil in Council, Alaska.

PubMed

Kim, Hye Min; Jung, Ji Young; Yergeau, Etienne; Hwang, Chung Yeon; Hinzman, Larry; Nam, Sungjin; Hong, Soon Gyu; Kim, Ok-Sun; Chun, Jongsik; Lee, Yoo Kyung

2014-08-01

The subarctic region is highly responsive and vulnerable to climate change. Understanding the structure of subarctic soil microbial communities is essential for predicting the response of the subarctic soil environment to climate change. To determine the composition of the bacterial community and its relationship with soil properties, we investigated the bacterial community structure and properties of surface soil from the moist acidic tussock tundra in Council, Alaska. We collected 70 soil samples with 25-m intervals between sampling points from 0-10 cm to 10-20 cm depths. The bacterial community was analyzed by pyrosequencing of 16S rRNA genes, and the following soil properties were analyzed: soil moisture content (MC), pH, total carbon (TC), total nitrogen (TN), and inorganic nitrogen (NH4+ and NO3-). The community compositions of the two different depths showed that Alphaproteobacteria decreased with soil depth. Among the soil properties measured, soil pH was the most significant factor correlating with bacterial community in both upper and lower-layer soils. Bacterial community similarity based on jackknifed unweighted unifrac distance showed greater similarity across horizontal layers than through the vertical depth. This study showed that soil depth and pH were the most important soil properties determining bacterial community structure of the subarctic tundra soil in Council, Alaska. © 2014 The Authors. FEMS Microbiology Ecology published by John Wiley & Sons Ltd on behalf of the Federation of European Microbiological Societies.

S-World: A high resolution global soil database for simulation modelling (Invited)

NASA Astrophysics Data System (ADS)

Stoorvogel, J. J.

2013-12-01

There is an increasing call for high resolution soil information at the global level. A good example for such a call is the Global Gridded Crop Model Intercomparison carried out within AgMIP. While local studies can make use of surveying techniques to collect additional techniques this is practically impossible at the global level. It is therefore important to rely on legacy data like the Harmonized World Soil Database. Several efforts do exist that aim at the development of global gridded soil property databases. These estimates of the variation of soil properties can be used to assess e.g., global soil carbon stocks. However, they do not allow for simulation runs with e.g., crop growth simulation models as these models require a description of the entire pedon rather than a few soil properties. This study provides the required quantitative description of pedons at a 1 km resolution for simulation modelling. It uses the Harmonized World Soil Database (HWSD) for the spatial distribution of soil types, the ISRIC-WISE soil profile database to derive information on soil properties per soil type, and a range of co-variables on topography, climate, and land cover to further disaggregate the available data. The methodology aims to take stock of these available data. The soil database is developed in five main steps. Step 1: All 148 soil types are ordered on the basis of their expected topographic position using e.g., drainage, salinization, and pedogenesis. Using the topographic ordering and combining the HWSD with a digital elevation model allows for the spatial disaggregation of the composite soil units. This results in a new soil map with homogeneous soil units. Step 2: The ranges of major soil properties for the topsoil and subsoil of each of the 148 soil types are derived from the ISRIC-WISE soil profile database. Step 3: A model of soil formation is developed that focuses on the basic conceptual question where we are within the range of a particular soil property at a particular location given a specific soil type. The soil properties are predicted for each grid cell based on the soil type, the corresponding ranges of soil properties, and the co-variables. Step 4: Standard depth profiles are developed for each of the soil types using the diagnostic criteria of the soil types and soil profile information from the ISRIC-WISE database. The standard soil profiles are combined with the the predicted values for the topsoil and subsoil yielding unique soil profiles at each location. Step 5: In a final step, additional soil properties are added to the database using averages for the soil types and pedo-transfer functions. The methodology, denominated S-World (Soils of the World), results in readily available global maps with quantitative pedon data for modelling purposes. It forms the basis for the Global Gridded Crop Model Intercomparison carried out within AgMIP.

Cokriging of Electromagnetic Induction Soil Electrical Conductivity Measurements and Soil Textural Properties to Demarcate Sub-field Management Zones for Precision Irrigation.

NASA Astrophysics Data System (ADS)

Ding, R.; Cruz, L.; Whitney, J.; Telenko, D.; Oware, E. K.

2017-12-01

There is the growing need for the development of efficient irrigation management practices due to increasing irrigation water scarcity as a result of growing population and changing climate. Soil texture primarily controls the water-holding capacity of soils, which determines the amount of irrigation water that will be available to the plant. However, while there are significant variabilities in the textural properties of the soil across a field, conventional irrigation practices ignore the underlying variability in the soil properties, resulting in over- or under-irrigation. Over-irrigation leaches plant nutrients beyond the root-zone leading to fertilizer, energy, and water wastages with dire environmental consequences. Under-irrigation, in contrast, causes water stress of the plant, thereby reducing plant quality and yield. The goal of this project is to leverage soil textural map of a field to create water management zones (MZs) to guide site-specific precision irrigation. There is increasing application of electromagnetic induction methods to rapidly and inexpensively map spatially continuous soil properties in terms of the apparent electrical conductivity (ECa) of the soil. ECa is a measure of the bulk soil properties, including soil texture, moisture, salinity, and cation exchange capacity, making an ECa map a pseudo-soil map. Data for the project were collected from a farm site at Eden, NY. The objective is to leverage high-resolution ECa map to predict spatially dense soil textural properties from limited measurements of soil texture. Thus, after performing ECa mapping, we conducted particle-size analysis of soil samples to determine the textural properties of soils at selected locations across the field. We cokriged the high-resolution ECa measurements with the sparse soil textural data to estimate a soil texture map for the field. We conducted irrigation experiments at selected locations to calibrate representative water-holding capacities of each estimated soil textural unit. Estimated soil units with similar water-holding characteristics were merged to create sub-field water MZs to guide precision irrigation of each MZ, instructed by each MZ's calibrated water-holding properties.

Genetically engineered Pseudomonas putida X3 strain and its potential ability to bioremediate soil microcosms contaminated with methyl parathion and cadmium.

PubMed

Zhang, Rong; Xu, Xingjian; Chen, Wenli; Huang, Qiaoyun

2016-02-01

A multifunctional Pseudomonas putida X3 strain was successfully engineered by introducing methyl parathion (MP)-degrading gene and enhanced green fluorescent protein (EGFP) gene in P. putida X4 (CCTCC: 209319). In liquid cultures, the engineered X3 strain utilized MP as sole carbon source for growth and degraded 100 mg L(-1) of MP within 24 h; however, this strain did not further metabolize p-nitrophenol (PNP), an intermediate metabolite of MP. No discrepancy in minimum inhibitory concentrations (MICs) to cadmium (Cd), copper (Cu), zinc (Zn), and cobalt (Co) was observed between the engineered X3 strain and its host strain. The inoculated X3 strain accelerated MP degradation in different polluted soil microcosms with 100 mg MP kg(-1) dry soil and/or 5 mg Cd kg(-1) dry soil; MP was completely eliminated within 40 h. However, the presence of Cd in the early stage of remediation slightly delayed MP degradation. The application of X3 strain in Cd-contaminated soil strongly affected the distribution of Cd fractions and immobilized Cd by reducing bioavailable Cd concentrations with lower soluble/exchangeable Cd and organic-bound Cd. The inoculated X3 strain also colonized and proliferated in various contaminated microcosms. Our results suggested that the engineered X3 strain is a potential bioremediation agent showing competitive advantage in complex contaminated environments.

Predicting Soluble Nickel in Soils Using Soil Properties and Total Nickel

PubMed Central

Zhang, Xiaoqing; Li, Jumei; Wei, Dongpu; Li, Bo; Ma, Yibing

2015-01-01

Soil soluble nickel (Ni) concentration is very important for determining soil Ni toxicity. In the present study, the relationships between soil properties, total and soluble Ni concentrations in soils were developed in a wide range of soils with different properties and climate characteristics. The multiple regressions showed that soil pH and total soil Ni concentrations were the most significant parameters in predicting soluble Ni concentrations with the adjusted determination coefficients (Radj 2) values of 0.75 and 0.68 for soils spiked with soluble Ni salt and the spiked soils leached with artificial rainwater to mimic field conditions, respectively. However, when the soils were divided into three categories (pH < 7, 7–8 and > 8), they obtained better predictions with Radj 2 values of 0.78–0.90 and 0.79–0.94 for leached and unleached soils, respectively. Meanwhile, the other soil properties, such as amorphous Fe and Al oxides and clay, were also found to be important for determining soluble Ni concentrations, indicating that they were also presented as active adsorbent surfaces. Additionally, the whole soil speciation including bulk soil properties and total soils Ni concentrations were analyzed by mechanistic speciation models WHAM VI and Visual MINTEQ3.0. It was found that WHAM VI provided the best predictions for the soils with pH < 7, was relatively reasonable for pH 7 to 8, and gave an overestimation for pH > 8. The Visual MINTEQ3.0 could provide better estimation for pH < 8 and meanwhile quite reasonable results for pH > 8. These results indicated the possibility and applicability of these models to predict soil soluble Ni concentration by soil properties. PMID:26217951

Predicting Soluble Nickel in Soils Using Soil Properties and Total Nickel.

PubMed

Zhang, Xiaoqing; Li, Jumei; Wei, Dongpu; Li, Bo; Ma, Yibing

2015-01-01

Soil soluble nickel (Ni) concentration is very important for determining soil Ni toxicity. In the present study, the relationships between soil properties, total and soluble Ni concentrations in soils were developed in a wide range of soils with different properties and climate characteristics. The multiple regressions showed that soil pH and total soil Ni concentrations were the most significant parameters in predicting soluble Ni concentrations with the adjusted determination coefficients (Radj2) values of 0.75 and 0.68 for soils spiked with soluble Ni salt and the spiked soils leached with artificial rainwater to mimic field conditions, respectively. However, when the soils were divided into three categories (pH < 7, 7-8 and > 8), they obtained better predictions with Radj2 values of 0.78-0.90 and 0.79-0.94 for leached and unleached soils, respectively. Meanwhile, the other soil properties, such as amorphous Fe and Al oxides and clay, were also found to be important for determining soluble Ni concentrations, indicating that they were also presented as active adsorbent surfaces. Additionally, the whole soil speciation including bulk soil properties and total soils Ni concentrations were analyzed by mechanistic speciation models WHAM VI and Visual MINTEQ3.0. It was found that WHAM VI provided the best predictions for the soils with pH < 7, was relatively reasonable for pH 7 to 8, and gave an overestimation for pH > 8. The Visual MINTEQ3.0 could provide better estimation for pH < 8 and meanwhile quite reasonable results for pH > 8. These results indicated the possibility and applicability of these models to predict soil soluble Ni concentration by soil properties.

Soil organic matter as sole indicator of soil degradation.

PubMed

Obalum, S E; Chibuike, G U; Peth, S; Ouyang, Y

2017-04-01

Soil organic matter (SOM) is known to play vital roles in the maintenance and improvement of many soil properties and processes. These roles, which largely influence soil functions, are a pool of specific contributions of different components of SOM. The soil functions, in turn, normally define the level of soil degradation, viewed as quantifiable temporal changes in a soil that impairs its quality. This paper aims at providing a generalized assessment of the current state of knowledge on the usefulness of SOM in monitoring soil degradation, based on its influence on the physical, chemical and biological properties and processes of soils. Emphasis is placed particularly on the effect of SOM on soil structure and availability of plant nutrients. Although these properties are discussed separately, the soil system is of dynamic and interactive nature, and changes in one property will likely affect other soil properties as well. Thus, functions of SOM almost always affect various soil properties and processes and engage in multiple reactions. In view of its role in soil aggregation and erosion control, in availability of plant nutrients and in ameliorating other forms of soil degradation than erosion, SOM has proven to be an important indicator of soil degradation. It has been suggested, however, that rather than the absolute amount, temporal change and potential amount of SOM be considered in its use as indicator of soil degradation, and that SOM may not be an all-purpose indicator. Whilst SOM remains a candidate without substitute as long as a one-parameter indicator of soil degradation is needed, narrowing down to the use of its labile and microbial components could be more appropriate, since early detection is important in the control and management of soil degradation.

Lessons learned: Are engineered nanomaterials toxic to terrestrial plants?

PubMed

Reddy, P Venkata Laxma; Hernandez-Viezcas, J A; Peralta-Videa, J R; Gardea-Torresdey, J L

2016-10-15

The expansion of nanotechnology and its ubiquitous applications has fostered unavoidable interaction between engineered nanomaterials (ENMs) and plants. Recent research has shown ambiguous results with regard to the impact of ENMs in plants. On one hand, there are reports that show hazardous effects, while on the other hand, some reports highlight positive effects. This uncertainty whether the ENMs are primarily hazardous or whether they have a potential for propitious impact on plants, has raised questions in the scientific community. In this review, we tried to demystify this ambiguity by citing various exposure studies of different ENMs (nano-Ag, nano-Au, nano-Si, nano-CeO2, nano-TiO2, nano-CuO, nano-ZnO, and CNTs, among others) and their effects on various groups of plant families. After scrutinizing the most recent literature, it seems that the divergence in the research results may be possibly attributed to multiple factors such as ENM properties, plant species, soil dynamics, and soil microbial community. The analysis of the literature also suggests that there is a knowledge gap on the effects of ENMs towards changes in color, texture, shape, and nutritional aspects on ENM exposed plants. Copyright © 2016 Elsevier B.V. All rights reserved.

Automatic identification of watercourses in flat and engineered landscapes by computing the skeleton of a LiDAR point cloud

NASA Astrophysics Data System (ADS)

Broersen, Tom; Peters, Ravi; Ledoux, Hugo

2017-09-01

Drainage networks play a crucial role in protecting land against floods. It is therefore important to have an accurate map of the watercourses that form the drainage network. Previous work on the automatic identification of watercourses was typically based on grids, focused on natural landscapes, and used mostly the slope and curvature of the terrain. We focus in this paper on areas that are characterised by low-lying, flat, and engineered landscapes; these are characteristic to the Netherlands for instance. We propose a new methodology to identify watercourses automatically from elevation data, it uses solely a raw classified LiDAR point cloud as input. We show that by computing twice a skeleton of the point cloud-once in 2D and once in 3D-and that by using the properties of the skeletons we can identify most of the watercourses. We have implemented our methodology and tested it for three different soil types around Utrecht, the Netherlands. We were able to detect 98% of the watercourses for one soil type, and around 75% for the worst case, when we compared to a reference dataset that was obtained semi-automatically.

The role of attached phase soil and sediment organic matter physicochemical properties on fullerene (nC60) attachment.

PubMed

McNew, Coy P; LeBoeuf, Eugene J

2015-11-01

Attached phase soil and sediment organic matter is ubiquitous in the subsurface environment, with a tendency to strongly sorb contaminants, and therefore it may play an important role in contaminant transport. In this study, the deposition of C60 nanoparticles onto attached phase Harpeth Humic Acid and Harpeth Fulvic Acid (HHA and HFA) is explored by using a quartz crystal microbalance with dissipation monitoring and systematically varying thermal energy. By comparing the C60 attachment onto HHA and HFA surfaces to that of bare silica and DLVO predictions, we find that the HHA and HFA layers hinder attachment at low temperatures, while HHA enhances attachment at higher temperatures. Based on thermal characterization of the HHA and HFA layers compared to the corresponding attachment trends, the attachment efficiency is strongly correlated with hydration of the layer. Possible mechanisms explaining this phenomenon include water-assisted disruption of polar SOM contacts and hydration-induced swelling of the AP-SOM matrix. Since humic substances typically dominate subsurface organic matter, these results may prove crucial to understanding the complex interactions of engineered nanomaterials in both the natural and engineered environment. Copyright © 2015 Elsevier Ltd. All rights reserved.

Stability of loess

USGS Publications Warehouse

Lutenegger, A.J.; Hallberg, G.R.

1988-01-01

Lutenegger, A.J. and Hallberg, G.R., 1988. Stability of loess. Eng. Geol., 25: 247-261. The natural stability of loess soils can be related to fundamental geotechnical properties such as Atterberg limits, water content and void ratio. Field observations of unstable conditions in loess deposits in the upper midwest, U.S.A. show relationships between instability and the in situ moisture content and the liquidity index of the loess. Unstable loess can attain natural moisture contents equal to, or greater than, its liquid limit. Implications of these observations for applied engineering works are described. ?? 1988.

Genome sequence of a microbial lipid producing fungus Cryptococcus albidus NT2002.

PubMed

Yong, Xiaoyu; Yan, Zhiying; Xu, Lin; Zhou, Jun; Wu, Xiayuan; Wu, Yuandong; Li, Yang; Chen, Zugeng; Zhou, Hua; Wei, Ping; Jia, Honghua

2016-04-10

Cryptococcus albidus NT2002, isolated from the soil in Xinjiang, China, appeared to have the ability to accumulate microbial lipid by utilizing various carbon sources. The predominant properties make it as a potential bio-platform for biodiesel production. Here, we report the complete genome sequence of C. albidus NT2002, which might provide a basis for further elucidation of the genetic background of this promising strain for developing metabolic engineering strategies to produce biodiesel in a green and sustainable manner. Copyright © 2016 Elsevier B.V. All rights reserved.

Physical and Social Impacts on Hydrologic Properties of Residential Lawn Soils

NASA Astrophysics Data System (ADS)

Smith, M. L.; Band, L. E.

2009-12-01

Land development practices result in compacted soils that filter less water, increase surface runoff and decrease groundwater infiltration. Literature review of soil infiltration rates reveals that developed sites’ rates, 0.1 to 24 cm/hr, are reduced when compared to rates of undeveloped sites, 14.7 to 48.7 cm/hr. Yet, most hydrologic models neglect the impacts of residential soil compaction on infiltration and runoff. The objectives of this study included: determination of differences between soil properties of forested and residential lawn sites in Baltimore Ecosystem Study; parcel-scale location impacts on soil properties; and the impact of social and physical factors on the distribution of soil properties of residential lawns. Infiltration measures were collected in situ using a Cornell Sprinkle Infiltrometer and soil cores were collected for water retention and texture analysis. These soil properties were paired with GIS data relating to age of house construction, property value, parcel area, percent canopy cover per parcel and parcel distance from stream. The study finds that saturated infiltration rates in residential lawn soils are significantly lower than forest soils due to reduced macroporosity of residential lawn soils. Intra-parcel differences in bulk density and soil depth indicate that runoff from residential lawns is more likely from near-house and near-curb locations than the mid-front or backyards. The range of infiltration rate, bulk density and percent organic matter can be explained by readily attainable social and physical factors—age of house construction and parcel distance to stream. The impacts of land management on soil properties appear to be more prominent than percent canopy.

Using IKONOS Imagery to Estimate Surface Soil Property Variability in Two Alabama Physiographies

NASA Technical Reports Server (NTRS)

Sullivan, Dana; Shaw, Joey; Rickman, Doug

2005-01-01

Knowledge of surface soil properties is used to assess past erosion and predict erodibility, determine nutrient requirements, and assess surface texture for soil survey applications. This study was designed to evaluate high resolution IKONOS multispectral data as a soil- mapping tool. Imagery was acquired over conventionally tilled fields in the Coastal Plain and Tennessee Valley physiographic regions of Alabama. Acquisitions were designed to assess the impact of surface crusting, roughness and tillage on our ability to depict soil property variability. Soils consisted mostly of fine-loamy, kaolinitic, thermic Plinthic Kandiudults at the Coastal Plain site and fine, kaolinitic, thermic Rhodic Paleudults at the Tennessee Valley site. Soils were sampled in 0.20 ha grids to a depth of 15 cm and analyzed for % sand (0.05 - 2 mm), silt (0.002 -0.05 mm), clay (less than 0.002 mm), citrate dithionite extractable iron (Fe(sub d)) and soil organic carbon (SOC). Four methods of evaluating variability in soil attributes were evaluated: 1) kriging of soil attributes, 2) co-kriging with soil attributes and reflectance data, 3) multivariate regression based on the relationship between reflectance and soil properties, and 4) fuzzy c-means clustering of reflectance data. Results indicate that co-kriging with remotely sensed data improved field scale estimates of surface SOC and clay content compared to kriging and regression methods. Fuzzy c-means worked best using RS data acquired over freshly tilled fields, reducing soil property variability within soil zones compared to field scale soil property variability.

State-Space Estimation of Soil Organic Carbon Stock

NASA Astrophysics Data System (ADS)

Ogunwole, Joshua O.; Timm, Luis C.; Obidike-Ugwu, Evelyn O.; Gabriels, Donald M.

2014-04-01

Understanding soil spatial variability and identifying soil parameters most determinant to soil organic carbon stock is pivotal to precision in ecological modelling, prediction, estimation and management of soil within a landscape. This study investigates and describes field soil variability and its structural pattern for agricultural management decisions. The main aim was to relate variation in soil organic carbon stock to soil properties and to estimate soil organic carbon stock from the soil properties. A transect sampling of 100 points at 3 m intervals was carried out. Soils were sampled and analyzed for soil organic carbon and other selected soil properties along with determination of dry aggregate and water-stable aggregate fractions. Principal component analysis, geostatistics, and state-space analysis were conducted on the analyzed soil properties. The first three principal components explained 53.2% of the total variation; Principal Component 1 was dominated by soil exchange complex and dry sieved macroaggregates clusters. Exponential semivariogram model described the structure of soil organic carbon stock with a strong dependence indicating that soil organic carbon values were correlated up to 10.8m.Neighbouring values of soil organic carbon stock, all waterstable aggregate fractions, and dithionite and pyrophosphate iron gave reliable estimate of soil organic carbon stock by state-space.

Soil engineering facilitates Downy brome (Bromus tectorum L.) growth - A case study

USDA-ARS?s Scientific Manuscript database

Some exotic plants are able to engineer new host soils and engender characteristics that potentially increase their growth. We hypothesized that this positive feedback may be a facet in the competitiveness of the exotic annual grass downy brome. Using rhizotrons in the greenhouse, we compared the gr...

Laboratory Assessment of the Mobility of Water-Dispersed Engineered Nanoparticles in a Red Soil (Ultisol)

EPA Science Inventory

Soils are major sinks of engineered nanoparticles (ENPs) as results of land applications of sewage sludge, accidental spills, or deliberate applications of ENPs (e.g., nano-pesticides). In this study, the transport behaviors of four widely used ENPs (titanium dioxide [TiO2], buck...

Recent development in preparation of European soil hydraulic maps

NASA Astrophysics Data System (ADS)

Toth, B.; Weynants, M.; Pasztor, L.; Hengl, T.

2017-12-01

Reliable quantitative information on soil hydraulic properties is crucial for modelling hydrological, meteorological, ecological and biological processes of the Critical Zone. Most of the Earth system models need information on soil moisture retention capacity and hydraulic conductivity in the full matric potential range. These soil hydraulic properties can be quantified, but their measurement is expensive and time consuming, therefore measurement-based catchment scale mapping of these soil properties is not possible. The increasing availability of soil information and methods describing relationships between simple soil characteristics and soil hydraulic properties provide the possibility to derive soil hydraulic maps based on spatial soil datasets and pedotransfer functions (PTFs). Over the last decade there has been a significant development in preparation of soil hydraulic maps. Spatial datasets on model parameters describing the soil hydraulic processes have become available for countries, continents and even for the whole globe. Our aim is to present European soil hydraulic maps, show their performance, highlight their advantages and drawbacks, and propose possible ways to further improve the performance of those.

Creep behavior of soil nail walls in high plasticity index (PI) soils : technical report.

DOT National Transportation Integrated Search

2017-04-01

An aspect of particular concern in the Geotechnical Engineering Circular No. 7: Soil Nail Walls (i.e., the soil : nail wall manual and construction guidelines) is the creep behavior of soil nail systems in high-plasticity : clays. This research proje...

Adsorption properties of subtropical and tropical variable charge soils: Implications from climate change and biochar amendment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, Ren-Kou; Qafoku, Nikolla; Van Ranst, Eric

2016-01-25

This review paper attempts to summarize the progress made in research efforts conducted over the last years to study the surface chemical properties of the tropical and subtropical soils, usually called variable charge soils, and the way they response to different management practices. The paper is composed of an introductory section that provides a brief discussion on the surface chemical properties of these soils, and five other review sections. The focus of these sections is on the evolution of surface chemical properties during the development of the variable charge properties (second section), interactions between oppositely charged particles and the resultingmore » effects on the soil properties and especially on soil acidity (third section), the surface effects of low molecular weight organic acids sorbed to mineral surfaces and the chemical behavior of aluminum (fourth section), and the crop straw derived biochar induced changes of the surface chemical properties of these soils (fifth section). A discussion on the effect of climate change variables on the properties of the variable charge soils is included at the end of this review paper (sixth section).« less

Method for modeling the gradual physical degradation of a porous material

DOE Office of Scientific and Technical Information (OSTI.GOV)

Flach, Greg

Cementitious and other engineered porous materials encountered in waste disposals may degrade over time due to one or more mechanisms. Physical degradation may take the form of cracking (fracturing) and/or altered (e.g. increased) porosity, depending on the material and underlying degradation mechanism. In most cases, the hydraulic properties of degrading materials are expected to evolve due to physical changes occurring over roughly the pore to decimeter scale, which is conducive to calculating equivalent or effective material properties. The exact morphology of a degrading material in its end-state may or may not be known. In the latter case, the fully-degraded conditionmore » can be assumed to be similar to a more-permeable material in the surrounding environment, such as backfill soil. Then the fully-degraded waste form or barrier material is hydraulically neutral with respect to its surroundings, constituting neither a barrier to nor conduit for moisture flow and solute transport. Unless the degradation mechanism is abrupt, a gradual transition between the intact initial and fully-degraded final states is desired. Linear interpolation through time is one method for smoothly blending hydraulic properties between those of an intact matrix and those of a soil or other surrogate for the end-state.« less

Analytical solution for tension-saturated and unsaturated flow from wicking porous pipes in subsurface irrigation: The Kornev-Philip legacies revisited

NASA Astrophysics Data System (ADS)

Kacimov, A. R.; Obnosov, Yu. V.

2017-03-01

The Russian engineer Kornev in his 1935 book raised perspectives of subsurface "negative pressure" irrigation, which have been overlooked in modern soil science. Kornev's autoirrigation utilizes wicking of a vacuumed water from a porous pipe into a dry adjacent soil. We link Kornev's technology with a slightly modified Philip (1984)'s analytical solutions for unsaturated flow from a 2-D cylindrical pipe in an infinite domain. Two Darcian flows are considered and connected through continuity of pressure along the pipe-soil contact. The first fragment is a thin porous pipe wall in which water seeps at tension saturation; the hydraulic head is a harmonic function varying purely radially across the wall. The Thiem solution in this fragment gives the boundary condition for azimuthally varying suction pressure in the second fragment, ambient soil, making the exterior of the pipe. The constant head, rather than Philip's isobaricity boundary condition, along the external wall slightly modifies Philip's formulae for the Kirchhoff potential and pressure head in the soil fragment. Flow characteristics (magnitudes of the Darcian velocity, total flow rate, and flow net) are explicitly expressed through series of Macdonald's functions. For a given pipe's external diameter, wall thickness, position of the pipe above a free water datum in the supply tank, saturated conductivities of the wall and soil, and soil's sorptive number, a nonlinear equation with respect to the total discharge from the pipe is obtained and solved by a computer algebra routine. Efficiency of irrigation is evaluated by computation of the moisture content within selected zones surrounding the porous pipe.