Soil Characterization Research Articles

Uncovering soil compaction: performance of electrical and electromagnetic geophysical methods

Abstract. Monitoring soil structure is of paramount importance due to its key role in the critical zone as the foundation of terrestrial life. Variations in the arrangement of soil components significantly influence its hydro-mechanical properties and therefore its impact on the surrounding ecosystem. In this context, soil compaction resulting from inappropriate agricultural practices not only affects soil ecological functions, but also decreases the water-use efficiency of plants by reducing porosity and increasing water loss through superficial runoff and enhanced evaporation. In this study, we compared the ability of electric and electromagnetic geophysical methods, i.e., electrical resistivity tomography (ERT) and frequency-domain electromagnetic (FDEM) method, to assess the effects caused by both heavy plastic soil deformations generated by a super-heavy vehicle and the more common tractor tramlines on silty-loam soils. We then tested correlations between geophysical response and soil variables (i.e., penetration resistance, bulk density, and volumetric water content on collected samples) at different homogeneous areas defined by k-means clustering. This work is intended to be a contribution to clarify expectations about the use of geophysical techniques to rapidly investigate soil compaction at various spatial scales, dissecting their suitability and limitations. It also aims to contribute to the methodological optimization of agrogeophysical acquisitions and data processing in order to obtain accurate soil models through a non-invasive approach. Electrical prospecting has finer spatial resolution and allows a tomographic approach, requiring higher logistic demands and the need for ground galvanic contact. On the other hand, contactless electromagnetic induction methods can be quickly used to define the distribution of electrical conductivity in the shallow subsoil in an easier way. In general, compacted soil portions are imaged as high-electrical-conductivity anomalies relative to the context. Results, validated with traditional soil characterization, show the pros and cons of both techniques and how differences in their spatial resolution heavily influence the ability to characterize compacted areas with good confidence.

Soil Strength Parameters for the Sustainable Design of Unsupported Cuts Under Drained Conditions Using Reliability Analysis

Unsupported excavations are frequently performed in several geological and geotechnical projects, particularly for constructing roads and railways, and they are often carried out in different materials. The design of such cuts in soils needs the determination of representative values of its mechanical properties, particularly of the strength parameters, and the application of adequate safety factors. The procedure should ensure a sustainable design of those cuts, allowing for economical solutions that guarantee a low probability of geological–geotechnical failure. This paper assesses the reliability of unsupported cuts in soils, under drained conditions, assuming a Mohr–Coulomb strength criterion. Statistical meshes are generated considering the spatial variability of the friction angle and of the true effective cohesion, which are assumed to be uncorrelated. In this process, typical values of the coefficients of variation and of the horizontal and vertical scales of fluctuation are applied. Soil characterisation is simulated in each statistical mesh, and the characteristic values of the strength parameters are determined using statistical methods. Unsupported cuts of different heights and inclinations are designed using typical safety factors. Slope stability analyses are carried out using Random Finite Element Limit Analysis. The uncertainty in the actions is considered, and the probability of failure is determined by direct reliability analysis. The results show the relevance of the ratio between the scale of fluctuation and the excavation depth, the slope inclination, and the characteristic value of the soil strength parameters on the probability of failure. Values of adequate safety factors are proposed towards obtaining an appropriate probability of failure, compatible with the sustainable design of the cuts.

Advanced characterisation of groundwater contamination at a dumpsite: Methodology and assessment - Case study of a municipal solid waste dumpsite in India.

Groundwater (GW) contamination due to municipal solid waste (MSW) disposal in open dumpsites is a pressing global issue. Traditional GW assessment studies are limited to single-depth sampling from nearby wells/handpumps, providing limited insights into subsurface soil characteristics and are prone to cross-contamination. The present study introduces an innovative methodology integrating advanced techniques: Cone Penetration Testing (CPT), Hydraulic Profiling Tool (HPT), Continuous Soil Sampling, and Discrete GW Sampling. Conducted at an operational dumpsite in New Delhi, India, from January to February 2023, the site investigation program covered seven distinct locations to incorporate the entire dumpsite area. The investigation proceeded in stages, starting with subsurface soil characterisation using CPT and HPT, followed by extracting soil and GW samples using CPT and HPT data. Due to restrictions in the northeast direction, GW samples were directly extracted from borewells. The results revealed maximum and minimum concentrations of 171 items/l and 26 items/l of MPs, while ionic concentration reached 13,200ppm for Cl- and 4437ppm for SO4-2. A maximum of 0.721ppm, 0.663ppm and 0.948ppm concentration was observed for Ni, Cu and Mo in GW samples. Spearman correlation and principal component analysis underscore the influence of Ec, TDS, Na+1 and Cl-1 on GW quality. This integrated approach effectively identifies high-permeability layers, which are crucial for understanding contaminant dispersion, and ensures precise sampling at various depths with minimal cross-contamination. This research demonstrates the proposed methodology's effectiveness in providing more profound and precise insights into GW contamination dynamics and suggests its utility in forming the basis for more effective remediation and regulatory strategies.

Biodiversity and Soil Characterization of Ancestral Domain of the Tagbanua Tribe in Aborlan, Palawan, Philippines

This study was conducted to determine strategies to enhance the sustainable forest management practices of the Tagbanua tribe. Specifically to describe the biodiversity and soil characteristics of the ancestral domain. The modified belt-transect method for biodiversity assessment developed by B+WISER (2014), further modified by the Department of Environment and Natural Resources (DENR) in the assessment, was used in this study. Results of soil chemical analysis showed significant variations among various land uses. The ancestral domain had at least 73 plant species belonging to 34 families and 59 genera. Four (4) taxa whose SN/families were still undetermined and another three (3) genera under families Annonaceae, Meliaceae, and Sapindaceae were unidentified. It had 12 plant species that are threatened with one critically endangered based on the list of threatened Philippine plants of the DENR. On the other hand, a total of 372 birds representing 61 species from 29 families were recorded. The high Shannon-Weiner Diversity Index (H’=3.69) and Shannon’s Evenness (HE=0.90) values indicate high avifaunal diversity and equitable distribution among the detected species. Most of the conservation priority species recorded in the area are Palawan endemic species. The survival of these birds is threatened by extinction due to habitat loss. This observation emphasized the importance of the ancestral domain as a refuge for these endemic species and conservation priority areas.

Sorting and Weathering Trends of Soil at Gale Crater, Mars: Implications for Regional Pedological Processes

AbstractDetailed soil characterization at Gale crater based on in situ observations has revealed compositional trends within soils, while the physical and chemical processes underlying the compositional trends remain to be evaluated. Here we use the grain‐morphometrical and geochemical trends across the Wentworth‐classes of 48 in situ soil targets at Gale crater to evaluate underlying pedological processes and potential chemical weathering signatures. The concentration of olivine minerals within the ∼250 to ∼500 μm size range indicates the prevalence of heavy mineral sorting in a granulometric sense in Gale soils that surpasses the possible effect of the cratering‐induced mixing processes. The extent of olivine sorting in soils varies spatially and is influenced by the targets' aeolian setting. The finest portion of Gale soils (<125 μm) is likely a mixture of allochthonous sediment, globally sourced from atmospheric suspension, and autochthonous counterparts from the weathering of local rocks, while the coarser soils (>125 μm) are mostly sourced from local rocks, with possible inputs from both the unaltered parent rock of the Stimson formation and the bedrocks that have undergone diagenetic alteration. If applicable globally, this would reinforce prior inferences that even dust‐mantled regions are geochemically heterogeneous owing to a substantial fraction of soils derived from underlying lithology. The low chemical weathering intensity and coupling of mobile elements in soils suggest localized, low pH and low water‐to‐rock ratio aqueous weathering conditions under predominantly cold and arid climates, which may occur either during post‐pedogenetic alteration in soils or during the acidic alteration of source rocks.

Dynamic Analysis of Soil-Structure Interaction in Earthquake-Prone Areas

This study used a thorough experimental method to examine the dynamic interaction between soil and structures in earthquake-prone locations. The study challenge concentrated on how different soil types and configurations influence the diversity of structural reactions under seismic loading conditions. The research utilized a mixed methods approach, which involved quantitatively analyzing soil parameters and assessing structure dynamics. The methods employed included the creation of scaled replicas depicting common architectural structures situated on various soil types, including sandy, clayey, and mixed compositions. We used high-precision sensors to record ground motion characteristics such as Acceleration, velocity, and Displacement. The data was then evaluated using statistical methods such as ANOVA and regression analysis. The results revealed substantial differences in the structural reaction based on the type of soil and the parameters of the structure. Structures built on sandy soils saw greater peak accelerations (up to 0.170 g) but smaller displacements. On the other hand, structures on clayey soils had moderate accelerations (up to 0.140 g) but had bigger inter-story drifts. The varied soil layers, ranging from 1.500 Hz to 1.780 Hz, influenced the natural frequencies of the buildings. The damping ratios ranged from 5.000% to 7.800%, indicating that structural damping effectively reduces seismic forces. The results emphasized the critical importance of the interaction between soil and structures in seismic design and the necessity for customized engineering solutions based on the individual soil conditions at the site. Suggested measures include improving methods for soil characterization, optimizing structural dynamics using cutting-edge dampening technologies, and upgrading seismic design codes to enhance the ability of structures to withstand earthquakes in places prone to seismic activity.

A case study: Thermophysics characterization of tropical soils extracted in the horizons HA and HB

A case study: Thermophysics characterization of tropical soils extracted in the horizons HA and HB

Volcanic red soil in the tropical mountain region: landscape, parent materials, engineering characteristics, and its use on slope stability (case study: West Lampung, Sumatra, Indonesia)

ABSTRACT The characterization of tropical mountain volcanic red soil in the tropical mountain region, West Lampung area, Sumatra, Indonesia concerning the landslide disaster has been carried out. The research methods used in this research are remote sensing methods, field geological mapping, petrographic analysis (thin section analysis), soil geotechnical analysis, soil geochemical analysis, slope stability analysis, and statistical analysis. The findings indicated that the study area’s volcanic red soil is distinguished by rolling hills with a V-shaped valley, a moderate to severe incline, and an elevation ranging from 850 to 1150 m above sea level. The soil is volcanic residual soil which resulted in wet tropics and from tuff layer and tuffaceous breccias in the felsic composition of the hydrothermal alteration environment. The soil of the study area has a reddish-brown color, and loose characteristic, and belongs to the type of very loose to solid high plasticity uniform inorganic sandy clayey silt. Based on saturated soil slope stability analysis, volcanic red soil has a stable to unstable category if forming a slope. The intrinsic factor that affects the stability of the slope is the percentage of clay content, electrical sensitivity, plasticity index, degree of saturation, and percentage of clay mineral content.

Editorial: Multiscale characterizations of special soils and the geotechnical implications

Editorial: Multiscale characterizations of special soils and the geotechnical implications

Characterization and Classification of Soils of Chamba Block of Tehri Garhwal District of Uttarakhand, India: A Case Study from Lesser Himalayas

In the present study, an attempt was made to characterize and classify the soils occurring on different topography in the Chamba block of Tehri Garhwal district of Uttarakhand. A detailed soil survey was carried out by simple random sampling and studying master profiles using Landscape Ecological Unit’s map on 1:10000 scale to study the soils. The high-resolution remote sensing data product derived from the IRS-R2, specifically the LISS-IV data and GIS approaches were used. Nine representative pedons (covering all the soil types) were studied for their morphological, physical and chemical properties. These soils were very shallow to deep, dark grayish brown to dark brown/dark yellowish brown, brown to dark yellowish brown, dark grayish brown to olive brown and very dark grayish brown to dark yellowish brown in colour. Structure of the surface soils varied from sub-angular blocky to disturbed to single grain.Soil texture varied fromsandy loam to sandy loam, sandy loam to loam, loamy sand to sand and loam to clay loam in texture, strongly acidic to acidic (<5.5-6.5) and neutral (6.5-7.5) in reaction. The electric conductivity exhibited a range from 0.17 to 1.83 dS m-1 within surface horizons and from 0.02 to 0.80 dS m-1 within the sub-surface horizons, accompanied by organic carbon content categorized as medium (0.50-0.75%) to high (>0.75%). The exchangeable cations, specifically Ca2+, Mg2+, Na+, and K+, demonstrated variability ranging from 4.90 to 10.40, 1.30 to 4.00, 0.39 to 1.01, and 0.44 to 1.27 cmol p+kg-1, respectively, in surface horizons. Base saturation (BS) varied from 80 to 92% in surface horizons and from 68 to 91% in the sub-surface horizons. The cation exchange capacity (CEC) varied between 8.6 to 19.9 cmol p+kg-1 in surface horizons and from 2.7 to 17.2 cmol p+kg-1 in the sub-surface horizons. The soils were classified within the Entisols and Inceptisols orders. To ensure sustainable agricultural production within these soils, it is imperative to implement appropriate management strategies to mitigate the impacts of soil degradation.

Integrating downhole seismic testing into dynamic probing light (DPL): first results

Dynamic probing light (DPL) is available among a wide range of dynamic penetrometers. This equipment can be used in locations where conventional sounding equipment may have limited access. Here, the shear wave velocity (Vs) determination by the downhole seismic technique is incorporated to the DPL to develop a hybrid test, the seismic DPL test, for the preliminary characterization of tropical soils. The corresponding equipment, test procedure and data interpretation of the seismic DPL (S-DPL) test are presented and discussed. S-DPL test campaigns were carried out at two experimental research sites where crosshole seismic tests were conducted to provide reference Vs profiles. The Vs profiles determined with the S-DPL test are in accordance with those determined with the crosshole test for both sites. The proposed hybrid test (S-DPL) has the potential to serve applications in preliminary site characterization, particularly at sites including unsaturated tropical soil profiles.

Engineering Geological Characterization and Slope Stability Analysis of Soils Along the Blue Nile Basin Road Section, Northwestern Ethiopia

Engineering Geological Characterization and Slope Stability Analysis of Soils Along the Blue Nile Basin Road Section, Northwestern Ethiopia

Modified Complex Electrical Resistivity Technique: Applications to Saturated and Unsaturated Soils

Abstract Direct current (DC) electrical resistivity is a common laboratory soil characterization method to support geotechnical infrastructure design and to supplement site investigations. The complex electrical resistivity method has the potential to provide additional electrical soil properties to enhance electrical soil characterization. Both methods are conventionally performed under fully saturated soil conditions; however, many environments exist where soil is not fully saturated, such as ballast structure supporting railways. In this study, a new experimental setup featuring a current enhancing agent (agar) for complex electrical resistivity testing is evaluated by testing five different soil specimens reconstituted at saturated and unsaturated conditions. Results showed that the new experimental setup is valid and can be used to obtain repeat measurements, particularly for specimens reconstituted in the unsaturated conditions where the traditional DC electrical resistivity setup yields results that are unreliable. This is one of the very few studies where tolerances for triplicate specimens are reported to establish differences in measurements from sample preparation versus discernable variability between different geomaterials. Additionally, all results are supported by a Cole-Cole model. The results show that the additional data collected in a complex electrical resistivity test can be used to differentiate different soil types that are ambiguous with the DC electrical resistivity method. The additional data have the potential to more fully characterize the electrical properties of saturated and unsaturated soils, as well as to help distinguish unique geophysical signatures of various geomaterials to enhance a geophysical site investigation for identifying soil variability in the subsurface.

Characterization and classification of soils of farm, Vasantrao Naik Marathwada Krishi Vidyapeeth, Parbhani by using RS and GIS techniques

Characterization and classification of soils of farm, Vasantrao Naik Marathwada Krishi Vidyapeeth, Parbhani by using RS and GIS techniques

Electrokinetic remediation of chromium contaminated soil: Impact of particle size on treatment efficiency and bioavailability

The electrokinetic remediation (EKR) is a potential method employed for removal and recovery of heavy metals from soil and various waste materials. However, it demonstrated promising efficacy in laboratory settings, diminished in practical implementations as a result of insufficient comprehension of in-situ conditions. In this study, experimental investigations were conducted to determine the effect of soil particle size on the performance of EKR. Four distinct soil particle sizes were utilized i.e., retained on 1.18 mm (EKR-A), 300 μm (EKR-B), 150 μm (EKR-C), and passing through 150 μm (EKR-D). The alteration in bioavailability as well as physiochemical properties of Chromium (Cr) was investigated through sequential extraction process (SEP) along with soil characterization techniques such as FE-SEM-EDX, XRD, FT-IR. Studies of soil particle size, composition and morphology indicate that as particle size decreases, pollutant concentration increases. Consensus was reached through the research that the treatment efficiency is substantially impacted by the particle size of the soil; in other words, smaller particle sizes led to diminished efficacy. The cumulative Cr removal percentages for EKR-A, EKR-B, EKR-C, and EKR-D were achieved as 27%, 19%, 10%, and 7%, respectively. The SEP study revealed that the initial soil Cr concentration was predominated with oxidizable fraction (63-81%) and the EKR facilitates the extraction of pollutants from the soil matrix by increasing their leachability from 1% to 30%, thus providing both removal and recovery of Cr as a feasible option.

Utility of dairy microbiome as a tool for authentication and traceability.

Milk microbiome contributes substantially to the formation of specific organoleptic and physicochemical characteristics of dairy products. The assessment of the composition and abundance of milk microbiota is a challenging task strongly influenced by many environmental factors. Specific dairy products may be designated by the Protected Designation of Origin (PDO) and Protected Geographical Indication (PGI) labeling, which however, occasionally fail to differentiate them according to specific quality characteristics, which are defined by different microbiota-driven reactions. Combining the above limitations, the scope of the present study, was to summarize the existing information toward three main issues. First, to assess the influence level of the diet type and grazing to rumen-GI tract, mammary gland, and udder microbiome formation in ruminants. Second, to discuss the factors affecting milk microbiota, as well as the effect of the endo-mammary route on milk microbial taxa. Lastly, to evaluate "milk microbiome" as a tool for product differentiation, according to origin, which will contribute to a more robust PDO and PGI labeling. Although the limitations are still a matter of fact (especially considering the sample collection, process, evaluation, and avoidance of its contamination), significant progress has been made, regarding the identification of the factors affecting dairy products' microbiota and its core composition. In conclusion, although so far not totally efficient in dairy products molecular identification, with the progress in soil, water, plant, and animal host's microbiota assembly's characterization, microbiomics could provide a powerful tool for authentication and traceability of dairy products.

Estimation of the Hydraulic Parameters of a Stratified Alluvial Soil in the Region of El Haouareb—Central Tunisia. Experiments, Empirical, Analytical and Inverse Models

Modeling water flow and contaminant transport in the unsaturated zone is a difficult task that relies heavily on good hydrodynamic soil characterization. This article presents a complementarity between experimentation, direct modeling and inverse modeling in order to provide a better estimate of the hydrodynamic parameters of stratified alluvial soil in the El Haouareb region of the Kairouane plain in Tunisia. A field sampling campaign was carried out. The samples collected underwent particle size analysis, bulk density measurements and infiltration tests using a mini-Muntz. In parallel, simple evaporation tests were applied to separate strata. In addition, a 2 m soil column was reconstituted and fitted with sensors to monitor water content, tension, temperature and electrical conductivity. An internal drainage test was performed on this monolith. Three methods were applied using experimental data to estimate soil hydrodynamic parameters. In the first method, pedotransfer functions were used (Rosetta platform) based on granulometric results and bulk density. In the second, water tension and water content monitored during the simple evaporation test were used to plot the soil–water retention curve (SWRC) using SWRC-Fit. In the third method, inverse modeling was applied to the internal drainage test. A comparison of the results showed that the inverse method had the lowest RMSE. Uncertainty analysis has been implemented for both the experimental and numerical set up.

Recovery and Restructuring of Fine and Coarse Soil Fractions as Earthen Construction Materials

Excessive consumption of natural resources to meet the growing demands of building and infrastructure projects has put enormous stress on these resources. On the other hand, a significant quantity of soil is excavated for development activities across the globe and is usually treated as waste material. This study explores the potential of excavated soils in the Brittany region of France for its reuse as earthen construction materials. Characterization of soil recovered from building sites was carried out to classify the soils and observe their suitability for earthen construction materials. These characteristics include mainly Atterberg limits, granulometry, organic matter and optimum moisture content. Soil samples were separated into fine and coarse particles through wet sieving. The percentage of fines (particles smaller than 0.063 mm) in studied soil samples range from 28% to 65%. The methylene blue value (MBV) for Lorient, Bruz and Polama soils is 1, 1.2 and 1.2 g/100 g, and French classification (Guide de terrassements des remblais et des couches de forme; GTR) of soil samples is A1, B5 and A1, respectively. The washing of soils with lower fine content helps to recover excellent-quality sand and gravel, which are a useful and precious resource. However, residual fine particles are a waste material. In this study, three soil formulations were used for manufacturing earth blocks. These formulations include raw soil, fines and restructured soil. In restructured soil, a fine fraction of soil smaller than 0.063 mm was mixed with 15% recycled sand. Restructuring of soil fine particles helps to improve soil matrix composition and suitability for earth bricks. Compressed-earth blocks of 4 × 4 × 16 cm were manufactured at a laboratory scale for flexural strength testing by using optimum molding moisture content and compaction through Proctor normal energy. Compressive strength tests were performed on cubic blocks of size 4 × 4 × 4 cm. Mechanical testing of bricks showed that bricks with raw soil had higher resistance with a maximum of 3.4 MPa for Lorient soil. Removal of coarse particles from soil decreased the strength of bricks considerably. Restructuring of fines with recycled sand improves their granular skeleton and increases the compressive strength and durability of bricks.

Seismic resonance vulnerability assessment for different structural systems through soil characterization: application in Guadalajara city, Mexico

Seismic resonance vulnerability assessment for different structural systems through soil characterization: application in Guadalajara city, Mexico

Geotechnical Characterization of the Magdalena River Subsoil in Magangué, Colombia: A Study Using CPTu and SPT Tests

This study employs Cone Penetration Tests (CPTu) and Standard Penetration Tests (SPT) to analyze the geotechnical properties of the Magdalena River’s riverbed and banks. While these methods are standard in soil characterization, this research innovatively combines CPTu’s continuous profiling with SPT’s localized sampling to develop a nuanced stratigraphic model of the subsurface. This integrated approach provides a comprehensive view of the soil conditions, which is crucial for understanding sediment variability and stability along the riverbanks. The findings from this methodological integration enhance our ability to predict soil behavior under dynamic riverine conditions, offering valuable insights for erosion control and sustainable river management. The study underscores the practical benefits of synergizing traditional testing methods to address geotechnical challenges in river environments.