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In recent years, individuals have begun to pay more attention to non-traditional stabilizers due to the problems connected with traditional stabilizers. Traditional stabilizers have undergone extensive investigation, and the mechanisms by which they act are well understood. This paper presents findings of the effect of sugarcane vinasse wastewater (VI) and sodium alginate (SA) polymer on the compressibility behavior, and microstructural evolution of clay soil using mixing method. The premise of this paper is to eliminate waste material from nature and compare the performance of this material against the use of polymers that have recently been used in improvement. The additives were dissolved in water and then introduced to the dried stratified soil to produce improved soil samples using the mixing technique. Transported unconfined compressive strength (UCS) was examined for 1, 14, and 28 days of treatments with additive ranges of 3–15% for VI and 0.25–1.25% for SA. In clay with high plasticity, the findings show that VI significantly influences increasing the UCS. With the addition of 9% vinasse to the soil at the age of 28 days, the UCS has increased by 78.8%. Additionally, the introduction of 1.25% SA to the soil has increased by 261.9% for the 28-day treatment efficiency significantly. Microstructural and chemical examination revealed that the mineralogical and morphological contents of the stabilized soil were influenced due to the pozzolanic reaction. The results showed that waste by-product liquid was able to significantly increase the strength and compressibility of the clay soil. Using a large volume of waste by-product liquid to stabilize soil, the researchers discovered a straightforward application method. [ABSTRACT FROM AUTHOR]

In response to the practical production challenges posed by the unreliable operation of the V-shaped squeezing soil-covering and -pressing device (VCP) for planters under clay soil conditions in Northeast China, incomplete seed furrow closure, and severe soil adhesion on pressing wheels, this study proposes a device with star-toothed concave discs for soil-covering and -pressing (STCP) with the aim of enhancing the soil-covering quality of planters. The main working principles of STCP were expounded, and its main structural and installation parameters were determined and designed. Based on bionics, with the dung beetle's protruding head structure as the research object and UHMWPE as the material, an optimized protuberance-type bionic pressing wheel was designed. A Box–Behnken experiment was conducted by taking the width of the compression wheel, the spring deformation, and the installation angle as experimental factors, as well as the weight of the soil adhered to the surface of the pressing wheel (SW) and the soil compactness (SC) as the evaluation indicators. The optimal structural parameters of the pressing device were determined as follows: the width of the pressing wheel was 60.57 mm, the spring deformation was 55.19 mm, and the installation angle was 10.70°. The field comparison tests of soil covering performance showed that the star-tooth concave disc soil-covering device can effectively solve the problem of seed "hanging" and "drying". The average covered soil weight of the star-tooth concave disc soil-covering device was 241.46 g, and the average covered soil weight of VCP was 223.56 g. Compared with VCP, the average covered soil weight of STCP increased by 8.01%. The variation coefficient of covered soil weight after the operation of the star-tooth concave disc soil-covering device was 3.71%, which was more uniform than VCP. The field comparison tests of soil-covering thickness showed that the uniformity of soil-covering thickness can be significantly improved by adding a star-tooth concave disc soil-covering device to VCP. The comparative tests of soil anti-adhesive showed that the convex hull type pressing wheels optimized by bionics had better soil anti-adhesive performance, and the soil adhesion weight was reduced by 43.68% compared with VCP. The field comparative tests of seedling emergence showed that the seedling emergence rate after STCP operation was 3.9% higher than that of VCP. [ABSTRACT FROM AUTHOR]

Identifying strength parameters under drained conditions is crucial for monitoring and evaluating long-term soil deformations caused by structures built on or in soils. Geotechnical engineers carry out direct shear tests (DSTs) and triaxial tests (TAs) in the laboratory to identify strength parameters under such conditions. However, it can take considerable time to ascertain the failure envelope of even a single soil in the TA tests commonly used to evaluate drained conditions. This study explores whether the effective internal friction angle (ϕ′)—as one of the drained shear strength parameters of remolded soils—can be identified with a vane shear test (VST) at very low (down to 0.001/min) rotation speeds, which is easy to implement and takes a relatively shorter time. For this aim, 18 different remolded soil samples with a wide range of plasticity were prepared using static compaction in the laboratory. DST tests were conducted under drained conditions to evaluate the drained shear strengths of the remolded soil samples. VST results indicate that the peak shear strength decreases with the rotation speed as expected. Shear strengths obtained from the slowest VSTs were correlated with ϕ′s from DSTs. While the results were not encouraging, it was observed that the results of VSTs still could be used in a predictive equation for ϕ′ which, as a function of LL and total density as well as VST strength parameter, the regression coefficient rose to 0.92. Some effective cohesion intercepts were observed during DSTs, which in turn somewhat reduce the predicted ϕ′s. [ABSTRACT FROM AUTHOR]

The piezocone penetration test (CPTu) is a common geotechnical field test to evaluate soil properties. In interpreting the CPTu field measurements, soil drainage conditions are mostly considered completely drained or undrained; however, partial drainage conditions govern for such soils as silts or clayey sand mixtures. Previous studies show that neglecting partial drainage conditions causes incorrect estimation of soil geotechnical parameters. Most studies have been conducted using calibration chambers and centrifuge tests on clayey soils. Due to the complications in modeling the piezocone test, few numerical studies have been performed under partially drained conditions, especially on coarse-grained soils. Among the challenges of numerical modeling of CPTu, one can mention the difficulty of modeling soil structure in large strain mode and soil–water interaction behavior. In this paper, piezocone penetration tests were modeled using the advanced hypoplastic constitutive model and finite-element method. The behavior of Firoozkooh sandy soil under different drainage conditions and relative densities was analyzed. Then, the effect of cone penetration on the surrounding soils was discussed. It was shown that drainage conditions and the soil relative densities significantly affected the trend of variations in excess pore-water pressure (EPWP) generated around the piezocone. [ABSTRACT FROM AUTHOR]

In this study, our objective was to investigate the effect of soil and altitude on the quality of some olive oils from different varieties of olive trees. The quality parameters, the chemical composition of the oils in fatty acids, as well as the profile in phenolic compounds by HPLC are determined and soil analyses are carried out. Statistical analysis of the data was performed using multivariate analysis (PCA). The results obtained showed that the highest concentrations of oleuropein derivatives and ligstroside derivatives were observed in chemlal oil (SBA) and the recorded values were 105.97 mg/Kg and 83.49 mg/Kg. Oleocanthal was found in all the tested samples, and it was higher in Chemlal oil (102.43 mg/kg). Phenolic compounds have affinities with soil clay content and altitude, palmitic and palmitoleic acids are influenced by organic matter content and soil pH. [ABSTRACT FROM AUTHOR]

Eucalyptus (Eucalyptus spp.) leads to depletion of nutrients from the soil due to its fast growing nature. Therefore, a pot experiment was conducted to study the effect of zinc (Zn) application on clonal eucalyptus growth, biomass output and its uptake, as well as response of eucalyptus to Zn in soils of three textures. The treatments consisted of eight levels of Zn (0, 5, 10, 15, 20, 25, 30, and 35 mg kg−1 applied through ZnSO4.H2O) in a completely randomized design triplicated in soils of three distinct textures (loamy sand, sandy loam and sandy clay). The plant height, collar diameter, dry weight of shoot and roots, soil plant analysis development (SPAD) readings, Zn concentration and uptake by leaves, stem+branches and roots increased significantly with Zn application. Average dry weight of shoot and roots (31.93 and 15.12 g plant−1, respectively) was significantly highest at 15 mg Zn kg−1 whereas Zn concentration and uptake (18.35 mg kg−1 and 286.2 µg plant−1, respectively) by roots were highest at 20 mg Zn kg−1. The above parameters differed significantly among soils as sandy clay>sandy loam>loamy sand except Zn content and uptake by roots and SPAD values which were highest in sandy loam soil. Loamy sand and sandy loam soil exhibited higher Zn use efficiency, shoot biomass response and uptake response to applied Zn than sandy clay soil. It is concluded to apply 20 mg Zn kg−1 in light soil and 15 mg Zn kg−1 in heavy textured soil for better growth and productivity of eucalyptus. [ABSTRACT FROM AUTHOR]

Advanced hyperspectral remote sensing technology can identify various clay minerals in the soil. The improved spectral and spatial resolution of the airborne hyperspectral sensor can be used for a better interpretation of clay mineral abundance in the soil. This research utilizes the high-resolution image data acquired from Advanced Visible Infrared Imaging Spectrometer Next Generation (AVIRIS-NG) on an airborne platform to map the abundance of clay minerals in the Udaipur region of Rajasthan (24° 34′ 16.5720′' N, 73° 41′ 29.5584′' E). The representative soil samples for various soil clay minerals, e.g., kaolinite, montmorillonite, and illite, were classified from AVIRIS-NG data using a spectral feature fitting algorithm. A total of thirty sites were selected from agricultural and wastelands for soil sample collection. X-ray diffraction (XRD) analysis of representative soil samples was carried out to find the percentage and type of clay minerals present. Regression analysis between absorption peak depth values estimated from the hyperspectral image of the sampling sites in the spectral region from 2205 to 2214 nm and corresponding clay content value showed a significant relationship. The regression line obtained for the known pixels was used to prepare the mineral abundance map over the study area. This study significantly indicates the dominance of montmorillonite clay mineral over kaolinite and illite in the soils of the Udaipur region. [ABSTRACT FROM AUTHOR]

The concept of soil organic carbon (SOC) saturation emerged a bit more than 2 decades ago as our mechanistic understanding of SOC stabilization increased. Recently, the further testing of the concept across a wide range of soil types and environments has led some people to challenge the fundamentals of soil C saturation. Here, we argue that, to test this concept, one should pay attention to six fundamental principles or "rights" (R's): the right measures, the right units, the right dispersive energy and application, the right soil type, the right clay type, and the right saturation level. Once we take care of those six rights across studies, we find a maximum of C stabilized by minerals and estimate based on current data available that this maximum stabilization is around 82 ± 4 g C kg -1 silt + clay for 2 : 1-clay-dominated soils while most likely being only around 46 ± 4 g C kg -1 silt + clay for 1 : 1-clay-dominated soils. These estimates can be further improved using more data, especially for different clay types across varying environmental conditions. However, the bigger challenge is a matter of which C sequestration strategies to implement and how to implement them in order to effectively reach this 82/46 g C kg -1 silt + clay in soils across the globe. [ABSTRACT FROM AUTHOR]

The concept of soil organic carbon (SOC) saturation emerged a bit more than 2 decades ago as our mechanistic understanding of SOC stabilization increased. Recently, the further testing of the concept across a wide range of soil types and environments has led some people to challenge the fundamentals of soil C saturation. Here, we argue that to test the concept, one should pay attention to 6 fundamental principles or rights (R's): the right measures, the right units, the right fractionation method, the right soil type, the right mineralogy, the right saturation level. Once we take care of those 6 rights across studies, we find a maximum of C stabilized by minerals and estimate based on current data available that this maximum stabilization is around 82 ± 4 g C kg-1 silt+clay for 2:1 clay dominated soils while most likely only around 46 ± 4 g C kg-1 silt+clay for 1:1 clay dominated soils. These estimates can be further improved using more data, especially for different mineralogies across varying environmental conditions. However, the bigger challenge is on how and which C sequestration strategies to implement in order to effectively reach this 82/46 g C kg-1 silt+clay in soils across the globe. In recent years, several studies (e.g., Begill et al. 2023; Salonen et al. 2023) have questioned the concept of soil carbon (C) saturation, i.e., organic C stabilized by soil minerals (Hassink, 1997; Six et al. 2002). Here, we want to draw attention to six fundamentals that we think one should be cognizant about when "testing" and "questioning" soil C saturation. [ABSTRACT FROM AUTHOR]

This Consolidation settlement is an important aspect of embankment work in various construction projects. This allows an engineer to estimate the value of the consolidation settlement and the length of time the consolidation will take. This study aims to analyze the consolidation settlement based on the consolidation parameters of the empirical relationship with the physical properties of clay soil. The research has begun with a consolidation test and an examination of the physical properties of clay soil on undisturbed soil samples. It has been followed by a search for an empirical relationship between consolidation parameters and clay soil properties. This equation is used to analyze the settlement in clay soils under embankment load. The results of the analysis show that the equations obtained have a similar shape to those from some previous studies. The use of moisture content, void ratio, and liquid limit of clay soil for the analysis of consolidation parameters has yielded positive results in estimating the consolidation settlement due to embankment load. [ABSTRACT FROM AUTHOR]

Soil stabilization is a critical step in numerous engineering projects, preventing soil erosion, increasing soil strength, and reducing the risk of subsidence. Due to its inexpensive cost and potential environmental benefits, waste materials, such as waste marble powder (WMP), have been used as additives for soil stabilization in recent years. This study investigates waste marble powder's effects on unconfined compressive strength (UCS) and clayey soil's ultrasonic pulse velocity (UPV) at different water contents and curing times, and artificial neural networks (ANNs) are also used to predict the UCS and UPV values based on three input variables (percentage of waste marble dust, curing time, and moisture content). Geo-engineering experiments (Atterberg limits, compaction characteristics, specific gravity, UCS, and UPV) and analytical methods (ANNs) are used. The study results indicate that the soil is high-plasticity clay (CH) using the Unified Soil Classification System (USCS), and adding waste marble powder (WMP) can significantly improve the UCS and UPV of clay soils, especially at optimal water content, curing times of 28 days, and 60% WMP. It is found that the ANN models accurately predict the UCS and UPV values with high correlation coefficients approaching 1. In addition, this study shows that the optimum water content and curing time for stabilized clay soils depend on the grade and amount of waste marble powder utilized. Overall, the study demonstrates the potential of waste marble dust as a soil stabilization additive and the usefulness of ANNs in predicting UCS and UPV values. This study's results are relevant to engineers and researchers working on soil stabilization projects, such as foundations and backfills. They can contribute to the development of sustainable and cost-effective soil stabilization solutions. [ABSTRACT FROM AUTHOR]

A novel graphical analysis-based method is proposed for analysing the responses of a cylindrical cavity expanding under undrained conditions in modified Cam Clay soil. The essence of developing such an approach is to decompose and represent the strain increment/rate of a material point graphically into the elastic and plastic components in the deviatoric strain plane. It allows the effective stress path in the deviatoric plane to be readily determined by solving a first-order differential equation with the Lode angle being the single variable. The desired limiting cavity pressure and pore pressure can be equally conveniently evaluated, through basic numerical integrations with respect to the mean effective stress. Some ambiguity is clarified between the generalised (work conjugacy-based) shear strain increments and the corresponding deviatoric invariants of incremental strains. The present graph-based approach is also applicable for the determination of the stress and pore pressure distributions around the cavity. When used for predicting the ultimate cavity/pore pressures, it is computationally advantageous over the existing semi-analytical solutions that involve solving a system of coupled governing differential equations for the effective stress components. It thus may serve potentially as a useful and accurate interpretation of the results of in situ pressuremeter tests on clay soils. [ABSTRACT FROM AUTHOR]

The present work determined the influence of superhydrophobic nano-SiO2 on the hydraulic conductivity and pore size distribution of expansive soil, and analysed the mechanism of modification between superhydrophobic nano-SiO2 and expansive soil from a microscopic view. Superhydrophobic nano-SiO2 was added to expansive soil as a modifier. Our samples were of two types, i.e., unmodified (without nano-SiO2) and modified (with 0.2%, 0.4%, 0.6%, 0.8%, and 1.0% nano-SiO2 by weight of the parent soil). The hydraulic conductivity decreased with increasing nano-SiO2 content. Fourier transform mid-infrared test revealed that some silanols in soil and nano-SiO2 were dehydrated and condensed to form siloxanes. We inferred that nano-SiO2 can attach onto the surface of soil particles to form a hydrophobic membrane, which reduced the soil expansion and the change in pore size distribution. And microscopic tests showed that the pore volume and hydrophilicity of the soil samples decreased with increasing SiO2 content. According to the Young–Laplace equation, the minimum permeable pore radius was calculated in the hydraulic-conductivity test. With increasing nano-SiO2 content, the volume of permeable pore decreased. It had an excellent linear relationship with the hydraulic conductivity and permeable pore volume of samples containing different nano-SiO2 contents. Therefore, superhydrophobic nano-SiO2 could effectively reduce hydraulic conductivity by changing the pore size distribution of expansive soil. [ABSTRACT FROM AUTHOR]

This study focuses on establishing a robust relationship between Standard Penetration Test-N values (SPT-N), geotechnical parameters and unconfined compressive strength (qu) using regression analysis. The proposed relationship offers a reliable method for estimating qu based on SPT-N values. A comprehensive dataset comprising approximately 200 soil samples collected from various boreholes across Dhaka city was utilized. Multiple Linear Regression (MLR), Rando-forest Regression (RFR) and AdaBoost Regression techniques were employed to develop a unified correlation model. Evaluation metrics including R-squared (R2), Mean Absolute Error (MAE) and Root Mean Squared Error (RMSE), along with Trend-behavior Analysis were employed to assess and compare the performances of the models. Additionally, sensitivity analysis was carried out on the selected model in order to assess the importance of each parameter used to predict qu. Finally, the selected model was compared against the existing empirical models that were published in previous studies. In terms of evaluation metrics and Trend-behavior Analysis, the results showed that the RFR model performed better than the others. Additionally, the selected model outperformed the others, demonstrating the highest R2 score, the smallest RMSE and MAE values and lower residuals compared to the previous models. Hence, the proposed model provides accurate predictions of qu for clayey soil in Bangladesh. Its implementation could ensure more efficient geotechnical designs, specifically adjusted to the geological conditions of the Dhaka region. While previous studies have established regional equations for various parts of the world, our model uniquely has incorporated the Plasticity Index (PI) as a predictor for qu and is specifically calibrated for the geological characteristics of Dhaka city. The findings of this study highlight the effectiveness and applicability of regression analysis in predicting qu for Dhaka's soil properties, thus introducing a valuable tool for enhancing the accuracy and effectiveness of geotechnical assessments and design in the region. [ABSTRACT FROM AUTHOR]

Currently, climate change has several negative impacts on the worldwide environment. One of them is land sliding due to rainfall precipitation. Commonly, mountainous areas have a high possibility of having such consequences. Unsaturated soil characterization is presented in this paper to demonstrate that the shifting of ground occurs at the surfaces of any slopes. The paper presents the simulation analysis on clayey soil slopes under extreme rainfall in Kazakhstan. The different slope heights and angles are selected to perform seepage and stability analysis in GeoStudio software. The results show that the slope is prone to failure due to the lower safety factor. It means the driving force is increasing during rainfall due to the increase in pore water pressures. As a result, the shear strength of the soil decrease. According to the results of the seepage analysis, the pore-water pressure has increased to almost 80 kPa at the mid-slope for each simulation. It leads to a decrease in suction and shear strength. The change of a factor of safety for the gentlest slope with 27 degrees angle is the lowest for 10 m slope height and the highest for 30 m slope height, whereas the change of safety factor for a slope with 45 degrees angle (9%) is almost the same for all slope heights. In other words, the factor of safety tends to reduce in all simulation cases, which confirms the loss of strength of soil due to a large amount of infiltration into the ground. [ABSTRACT FROM AUTHOR]

How to predict the long-term deformation of natural soft soils under embankments has been an important yet challenging issue in geotechnical and transportation engineering. The major difficulties lie in consolidation analyses of thick soil layers, modelling of the nonlinear time-dependent stress–strain behaviour of clayey soils, and proper determination of soil parameters. While finite element (FE) software has great advantages and wide applications in consolidation analyses, development of reliable simple methods, which can be conveniently used by engineers, is also needed. In this paper, both a fully coupled FE model and a simplified Hypothesis B method are developed and applied for long-term deformation analyses of two test embankments on the multi-layered Malaysian marine clays. FE simulations are conducted using PLAXIS with a nonlinear 3-D elastic visco-plastic (3-D EVP) model. A series of parametric studies are carried out on the influences of soil parameters and modelling techniques using this FE model. A simplified Hypothesis B method with the nonlinear 1-D EVP model and modifications for 2-D stress diffusion and buoyancy effects is derived and applied for estimating the long-term consolidation settlement curves of the two test embankments. It is found that the fully coupled FE model with the nonlinear 3-D EVP can simulate the long-term embankment displacements with good agreement with measured data. Parametric studies indicate that using averaged soil indices and updating static pore pressure have significant contributions to the accuracy of simulations. The settlements calculated by the improved simplified Hypothesis B method are found in close agreement with FE simulation results and measured data. [ABSTRACT FROM AUTHOR]

This study investigated the different geotechnical characteristics of soil stabilization with the addition of lime and rice husk ash (RHA) in varying amounts (3%, 5%, 7%, and 9% lime, and 4%, 8%, 12%, and 16% RHA). A series of compaction, unconfined compressive strength (UCS), California bearing ratio (CBR), pH, and X-ray diffraction (XRD) tests were performed in the laboratory to assess the impact of the considered admixtures on the stabilized soil parameters. This study also proposes the successful integration of an artificial neural network (ANN) and a Gaussian process regression (GPR) with the experimental UCS observations. The lime concentration, RHA concentration, and curing period were considered as the input parameters, and UCS was considered as the response. The proposed framework was extended to analyze the compressive behavior of treated soil on the minuscule level. Such coupled machine learning-based experimental investigation can provide deep insight into the soil behavior which otherwise would have remained unexplored due to the prohibitive nature of performing laboratory experiments on a large scale. The findings demonstrated the effectiveness of RHA in addition to lime in stabilizing the considered expansive soil. With the addition of lime and RHA mix, the UCS and CBR values of the treated soil increased significantly. [ABSTRACT FROM AUTHOR]

This paper discusses the second-order reliability-based design optimization (SORBDO) of unsaturated finite slopes. An efficient search algorithm is proposed to locate the most probable slip surfaces using the Morgenstern–Price method of slices. The variability of fitting parameters of the soil water characteristic curve (SWCC) and shear strength parameters have been taken into account for evaluating the reliability of unsaturated finite slopes. Six unsaturated shear strength (USS) models are considered for the analysis of unsaturated soils. The most conservative model for the optimum design of finite slopes is recommended. Moreover, the results indicate that the mean and standard deviation of the fitting parameters of SWCC have a significant effect on the critical centers, critical slip surfaces, and reliability index of the unsaturated finite slopes. The results demonstrate a significant change in the critical centers associated with critical slip surfaces due to the change in the mean and coefficient of variation of the fitting parameters of SWCC. Statistical analysis of the experimental data shows that a positive correlation exists between fitting parameters of SWCC related to air entry value (af) and residual water content (mf). Negative correlations are found between the fitting parameters of SWCC related to air entry value (af) and slope (nf). Similarly, the SWCC fitting parameters related to residual water content (mf) and slope (nf) have negative correlations for clayey soils. It is observed that the correlated value of the reliability index is overestimated with reference to the uncorrelated value for clayey soil slopes. The proposed design charts are beneficial for engineers and practitioners for the sustainable design of unsaturated finite slopes. Overall, the developed rigorous SORBDO framework offers a more rational approach for assessing critical failure surfaces and critical centers, considering the interdependency of random variables. [ABSTRACT FROM AUTHOR]

Clayey soils are treated with binding agents to improve their mechanical properties, as these soils are widely used in construction. The production of binding agents is an energy-intensive process and emits significant amounts of CO2. In addition, the interest in recycling industry waste materials has increased, and the management of significant waste from biomass power plants remains an issue. We used three biomass ashes derived from pellet, olive, and grapevine combustion as stabilizing agents of a clayey soil. The mechanical effects of the treatment on clay-ash mixtures were evaluated using confined compressive tests. The mixtures' chemo-mineralogical evolution was evaluated through X-ray powder diffraction and quantitative Rietveld analysis, Fourier transform infrared spectroscopy (FT-IR), and energy-dispersive X-ray spectroscopy coupled with scanning electron microscopy (EDS-SEM). The FT-IR spectra showed an evolution of the Si-O-Si/Al features, with shifting band positions due to polymerization of the tetrahedral units. The EDS-SEM analysis showed an evolution of the Ca/Si distribution and the growth of pozzolanic reaction products, such as C-S-H nanocrystals and gels. This evidence confirms that the pozzolanic reaction occurs by dissolution of clay minerals and/or the amorphous phase of the ash, which affects the macroscopic behavior of clayey soils in terms of stiffening and strengthening, as confirmed by mechanical tests, albeit these effects are non-homogenous and continuous. [ABSTRACT FROM AUTHOR]

Soil texture using a hydrometer or pipette method requires expertise, although these are accurate. A soil expert may help the farmer to detect the soil texture by analyzing the visual texture of the soil, which is not always accurate. This paper presents the smartphone image-based sand and clay soil classification in wet and dry humid conditions using Self Convolution Neural Network (SCNN) and finetuned MobileNet.A soil dataset of 576 soil images was prepared using a low-cost smartphone under natural light conditions. Different augmentation techniques such as shift, range, rotation, and zoom were applied to the soil dataset to increase the number of images in the soil dataset. The best performance of the MobileNet was reported at epoch 15 with a testing and training loss of 0.0091 and 0.0194, respectively. Though the SCNN model performed best at epoch 10 with a testing accuracy of 99.85%, the MobileNet reported less computation time (167.8s) than the SCNN (273.2s). The precision and recall of the models were 99.62 (MobileNet) and 99.84 (SCNN). The accuracy of the SCNN reported itself as the best model, whereas the computing time of the MobileNet reported itself as the best model in different humid conditions. The model can be used to replicate the traditional soil texture analysis method and the farmers can use it for better productivity. [ABSTRACT FROM AUTHOR]

An attempt has been made in this paper to conduct an Electrokinetic (EK) enhanced largescale model study to analyze the heaving phenomena observed in fields. The application of the EK technique on fields to study alkali-induced heaving has been simulated in the laboratory using a rectangular and circular model. The EK technique was mainly employed to facilitate alkali soil interaction. Analysis of the geometry of the model boundary on the various physiochemical as well as geotechnical properties of the soil was conducted. Before that, a simple heaving analysis was also performed in an oedometer without the EK technique. Compare to the maximum heaving of 5.55% observed in the oedometer the soil in EK-equipped circular and rectangular models showed the heaving of 5.42% and 4.21% respectively. The heaving pressure recorded for the oedometer was 67.5 t.m-2 while for the circular and rectangular models these values were 37.7 t.m-2 and 18.8 t.m-2 respectively. Further, the value of unconfined compressive strength of soil decreases from 141 kPa to 80 kPa after interaction with alkali and the decrease was more prominent in the circular EK model. However, there was an increase in the friction angle and a decrease in cohesion value after alkali interaction. The structural alteration due to alkali solution was examined by SEM and XRD analysis. [ABSTRACT FROM AUTHOR]

Several widely used field methods for estimating postliquefaction ground deformation are based on the laboratory data from one series of cyclic simple shear tests performed on one uniform clean sand reconstituted to three relative densities. It is not clear if the trends of this one data set are applicable to other clean sands, nonplastic silty sands, and nonplastic silts. A database of 579 test results on postliquefaction volumetric strain, including 299 test results that relate maximum shear strain to the factor of safety against liquefaction triggering, was compiled and used to examine trends for these soils. The database includes postcyclic test data on 10 clean sands, 2 gravels, 3 silty sands, 5 silts, and 3 clayey soils. The enlarged cyclic testing database was used to develop models that estimate postliquefaction volumetric strain and maximum shear strain as a function of soil type, state, and seismic demand. The models are applicable to uniform nonplastic soil. The state parameter was used in addition to relative density and void ratio to characterize the state of the soil. Correlations between these parameters enable the full data set to inform the models. [ABSTRACT FROM AUTHOR]

Supplemental fertilizer N recommendations for flood‐irrigated rice (Oryza sativa L.) have been developed with tests that quantify plant‐available N within the effective rooting depth. Alkaline hydrolyzable‐nitrogen (AH‐N) soil test methods were recently used to successfully guide supplemental fertilizer‐N management decisions of drill‐seeded, delayed‐flood rice, stimulating interest in evaluating additional indicators of N availability such as soil total carbon (STC) and soil total nitrogen (STN). Our first objective was to evaluate the relationship among STC, STN, and AH‐N to a depth of 60 cm. Our second objective was to correlate STC and STN to rice N uptake and grain yield and develop calibration regression models that identified the yield maximizing N rate (FN 95%RGY). The STC and STN were significantly and positively related to AH‐N when clayey soils were sampled to >15‐cm depth and the coefficient of determination (r2) exhibited a range of.22–.70 for STN and.26–.75 for STC. Overall, STC and STN were significantly related to rice N uptake, unfertilized grain yield (Yield0N), or relative grain yield (RGY) and r2 values tended to be greatest at a 30‐cm depth or only nominally improve when sampling depth exceeded 30 cm. Calibration of STC and STN to predict FN 95%RGY was successfully completed, but all linear regressions had r2 <.40. The influence of sampling depth on the ability of STC and STN to serve as indicators of rice response to supplemental N fertilization demonstrates the utility of sampling within the rice plant's effective rooting depth. Core Ideas: Soil total C and N increased linearly with alkaline hydrolyzable‐N to a 60‐cm depth.Soil total C and N explained <40% of the variability exhibited by rice response parameters.Soil total C and N from >30‐cm depth did not improve prediction of the rice grain yield maximizing fertilizer N rate.Correlation and calibration of soil total C and N to fertilizer N response of rice should consider the extent of rooting depth. [ABSTRACT FROM AUTHOR]

This study evaluates the strength behaviors and morphological characteristics of Lianyungang marine clay under the effect of porewater salinity. Soil at higher salinity was found to have increased internal friction angle and undrained shear strength. The difference in undrained shear strength enlarges as the confining pressure increases. Different stress paths were exhibited with soil at different salinities. Soil morphology analysis including scanning electron microscopy (SEM) and Image-Pro Plus (IPP) were employed to investigate the underlying mechanism of the enhanced strength behaviors of soft marine clay with increased salinity. Aggregated soil fabric was observed at higher salinity and contributed to enhanced strength. The results demonstrate that the aggregated soil structure is the primary mechanism responding to the enhanced strength behavior of marine clay under relatively high salinity (6%). Quantitative relationships were developed between the strength parameters and morphological characteristics of soil, i.e., area of particles, roundness of particles, area of pores, pore orientation, and fractal dimension of pore distribution, in the forms of empirical equations, and are expected to serve as the references for prediction in undrained behaviors of soft marine clays with known soil index. [ABSTRACT FROM AUTHOR]

This experimental study examines the efficacy of the inclusion of randomly distributed polypropylene fiber (PP) reinforcement on the engineering properties of expansive clays. The effect of PP fiber inclusions (0%-0.8%) on compaction, unconfined compressive strength (UCS), elastic modulus (E50), California bearing ratio (CBR) and swell-consolidation parameters of test soil were explored. Experimental results showed significant improvement in the strength parameters of treated soils with an optimal fiber content at about 0.4% by weight of soil. The swell-consolidation parameters were also observed to be significantly ameliorated in fiber-reinforced samples. Test results indicate that the use of PP fiber as a reinforced stabilizer for expansive clays not only benefits the sustainable utilization of fiber wastes in soil stabilization, but also reduces the environmental footprint globally. [ABSTRACT FROM AUTHOR]

The basic purpose of foundation design is to predict ultimate soil bearing (Qu) and to determine actual load-carrying capacities (Ru) at the final set installation. One specific case study was when the project owner was only allowed to use limited CPT data of the high-cost reason for complete soil investigation. Besides that, the location was not only relatively densely populated, but also the soil investigation work could cause some noise during the implementation of field-testing methods using SPT and Borlogs. CPT has been selected and easy in predicting the Qu value of a single pile. Two points at one of the configurations of single piles were evaluated randomly by the PDA test in determining the actual load capacity or Ru. In general conclusion, the Qu was less than Ru values for all existing points of the single pile at the study area. To find out other values of Qu and Ru in all piles were analyzed by a geospatial analysis. By using isotropic Moran's method, there was a positive autocorrelation in adjacent pile location since I = 0.1767 > I0 = - 0.25. Graphically, the semivariogram also validated Gaussian interpolation models as the best correlation in searching pair; distance; and semivariance values among the single pile. Finally, the ordinary Kriging method was used to plot all points graphically in 3 D based on Moran's and semivariogram of Qu and Ru data. Thus, this method yields good results of Qu and Ru for other single piles with an error of around 13.2% at the final set installation between 8.9 to 9.5 m. [ABSTRACT FROM AUTHOR]

Proximal soil sensing is a highly advanced and rapidly evolving technique for predicting soil chemical properties. NIR spectroscopy is expected to offer an easier and more cost-effective alternative to traditional soil chemical analysis methods for broader agricultural applications. This review aims to address the challenges in high-clay content soils by 1) understanding the relationship between NIR spectroscopy and its predictive capabilities of chemical properties, and 2) proposing the application of advanced technologies to improve their practical applications. The high-clay content soils increase the adsorption of various cations, including Al3+, Ca2+, Mg2+, K+, Na+, and NH 4 +, and affect crop root density, absorption area, and nutrient uptake efficiency. However, predicting soil characteristics using NIR spectra can be difficult due to the complex nature of soil metrics. Under clay-rich soils, the high moisture content leads to a significant presence of O-H vibrations (1395 and 1415 nm), which overlaps with crucial function groups. Recent advancements using deep learning models have significantly improved prediction accuracy and efficiency for soil properties. The results showed that the R² values for predicting soil organic C, total N, and pH were 0.94, 0.89, and 0.87 for S-AlexNet; 0.95, 0.94, and 0.90 for GADF-Swin Transformer; and 0.88, 0.84, and 0.87 for PLSR, respectively. Additionally, integrating hyperspectral and multispectral sensors further improves prediction efficiency by providing higher spatial and spectral resolutions. In conclusion, this review suggests that adopting cutting-edge technologies can improve the predictions accuracy of chemical properties in the clay-rich soils. Nevertheless, overcoming the limitations of advanced technologies, such as high computational resource requirements, is necessary for practical application in agriculture. [Display omitted] • Challenges of model prediction using NIR in soils with high clay content. • Impact of overtones in hydroxyl (O-H) functional groups on NIR spectral interpretation. • Advancements in model accuracy by noise reduction in NIR analysis. • Developing novel models for improved soil chemical property prediction. • Utilizing UAV and AI technologies for enhanced soil analysis. [ABSTRACT FROM AUTHOR]

The determination of the coefficient of linear extensibility (COLE) of soils is crucial for enhancing structural stability in civil engineering applications. Traditional methods for measuring COLE have some practical limitations. In routine soil analyses, clay and soil organic carbon (OC) are often measured, while soil hygroscopic water content (wh) is easy to determine on several soil samples simultaneously. The aims of the study were to (1) utilise two data partitioning approaches to develop regression models that estimate the soil COLE from hygroscopic water content, clay and OC contents, and (2) compare the model performance of the developed regression models. We used two data partitioning approaches. First, the calibration models were developed on 53 soil samples from Slovakia and validated with 24 soil samples from the United States (country‐wise). Second, the calibration models were built from 67% of the entire dataset and validated with 33% (mixed data). Regression models based on hygroscopic water content accurately estimated COLE regardless of sorption direction or data partitioning approach (RMSE: 0.014–0.023 cm cm−1). The inclusion of OC in multiple linear regression models of clay only marginally improved COLE estimation compared to clay alone. For all models, the mixed data partitioning method showed better model validation performance than the country‐wise approach. The COLE classes derived from the estimated COLE values compared favourably (72%–94% accurate) to the measured data. Thus, there is a great potential to estimate the COLE from readily available (clay and OC) or easily measurable (hygroscopic water content) soil properties. Highlights: Hygroscopic water content (wh) is intimately linked to soil properties that determine COLE.Regression models based on wh or clay, and organic carbon content accurately estimated COLE.Data partitioning approach for modelling significantly impacted model performanceSamples with very high COLE were better estimated by wh‐based models than by other variables [ABSTRACT FROM AUTHOR]

The adoption of mechanistic-empirical approach to pavement design requires the use of resilient modulus of subgrade soils as a crucial input. The determination of in the laboratory is inexpedient due to the nature of the existing test protocols. This prompted the use of estimated values, which inadvertently has gained popularity lately. However, the accuracy of estimated values is questionable due to spatial variability of soil properties. This necessitated the aggressive search for robust and thorough approaches for predictive modelling of the . In the present study, a systematic approach was adopted for the descriptive analysis and estimation of . from routine soil properties using data from Long-Term Pavement Performance (LTPP) and considering the spatial variability of the soil properties. Descriptive analysis was executed using non-parametric correlation and principal component analysis (PCA), while the estimation was done using three machine learning methods which include gradient boosting regression (GBR), adaptive neuro-fuzzy inference system (ANFIS) and artificial neural network (ANN). Based on the PCA, four factors which explained a total of 77.5% variance in the data had significant influence on the . These include the effect of moisture-induced changes on the soil consistency limits and physical condition, effect of the soil clay content, effect of the soil gradation and effect of the soil stress state. Various factors of the machine learning methods such as the learning rate, number of clusters and number of hidden layers had a significant effect on the prediction accuracy. The three machine learning methods were satisfactory for the prediction based on R2 values which were generally above 0.9. Also, when considering spatial variability of routine soil properties, the GBR and ANFIS have a comparative advantage over the ANN, since they exhibited a high stability in the prediction for both the training and testing dataset. [ABSTRACT FROM AUTHOR]

Stable hydrogen isotope ratios (δ2H values) in structural hydroxyl groups of pedogenic clay minerals are inherited from the surrounding water at the time of their formation. Only non‐exchangeable H preserves the environmental forensic and paleoclimate information (δ2Hn value). To measure δ2Hn values in structural H of clay minerals and soil clay fractions, we adapted a steam equilibration method by accounting for high hygroscopicity. Our δ2Hn values for USGS57 biotite (−95.3 ± SD 0.9‰) and USGS58 muscovite (30.7 ± 1.4‰) differed slightly but significantly from the reported δ2H values (−91.5 ± 2.4‰ and −28.4 ± 1.6‰), because the minerals contained 1.1%–4.4% of exchangeable H. The low SD of replicate measurements (n = 3) confirmed a high precision. The clay separation method including destruction of Fe oxides, carbonates and soil organic matter, and dispersion did not significantly change the δ2Hn values of five different clay minerals. However, we were unable to remove all organic matter from the soil clay fractions resulting in an estimated bias of 1‰ in two samples and 15‰ in the carbon‐richest sample. Our results demonstrate that δ2Hn values of structural H of clay minerals and soil clay fractions can be reliably measured without interference from atmospheric water and the method used to separate the soil clay fraction. Highlights: We tested steam equilibration to determine stable isotope ratios of structural H in clay.Gas‐tight capsule sealing in Ar atmosphere was necessary to avoid remoistening.Our steam equilibration method showed a high accuracy and precision.The clay separation method did not change stable isotope ratios of structural H in clay. [ABSTRACT FROM AUTHOR]

A method for determining the coefficient of viscosity based on the field tests of frozen clay soils by static penetration test in quasi-static or relaxation-creeping (with probe stabilization) modes is proposed. The method is developed on the basis of a comparative analysis of the dependence of the soil resistivity under the probe cone on the probing speed and laboratory test data for uniaxial compression. The verification of the method showed its applicability for preliminary evaluation of the coefficient of viscosity for plastic frozen clay soils. [ABSTRACT FROM AUTHOR]

The essential nature of dispersive clays was first noticed by U.S. Dams' soil scientists and agricultural engineers. Highway embankments and natural formations of high sodium dispersive clay were recorded as severely damaged by internal (tunnel) erosion of water flowing in the form of concentrated leaks within cracks. These dispersive clays, which cannot be differentiated from ordinary erosion-resistant clays by the routine civil engineering tests, erode rapidly in slow-moving (or even quiet) water by individual colloidal particles going into suspension. In Iraq, few studies were interested in such types of soils; that's why the present study takes into consideration dispersion of Baghdad clayey soil brought from three different Zones in Baghdad; the first soil is brought from Al. Kazaliyah district Zone (A), This Soil is classified as (CH) according to the Unified Soil Classification System (USCS). The second soil is brought from Al. Qadisiya District Zone (B) is classified as (CH), while the third Soil is Al. Dora region Zone (C) is classified as (CL). The conventional testing and interpretation are found to be inapplicable to analyze and identify the Dispersion soils due to the existence of Na+. The effect of water content was studied in two different tests for each soil; the pinhole test and soil retention test. The behavior of dispersive soil is not affected by water content, but water content may change the time to failure. This fact gives a good and new indicator of the maximum time to failure. [ABSTRACT FROM AUTHOR]

In this letter, the authors propose a microwave sensor capable to detect soil moisture content parameter for use in precision agriculture and agricultural smart monitoring applications. The novel sensor is based on complementary split‐ring resonator metamaterial topology, microstrip line and was built under biodegradable dielectric substrate of polylactic acid for sustainable purposes. The sensing mechanism relates the sensor's resonant frequency to the soil moisture content changes over time. For experimental validation purposes, a compact sensor prototype (75 mm × 35 mm × 1.55 mm and 12 g) with fundamental resonant frequency at 958 MHz was built and submitted to calibration process on typically sandy and clay soils to get fitting models capable to estimate soil moisture content. Simulated and experimental results are presented together and show good agreement with each other. The calibration data for both soil types were processed using the least‐squares method and the proposed curve‐fitting models are capable to estimate soil moisture content levels from 5% to 20% for sandy soil and from 12% to 23% for clay soil with satisfactory accuracy, proving the device viability. [ABSTRACT FROM AUTHOR]

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Additive Manufacturing (AM) techniques are under continuous investigation with interesting results published at both experimental and research levels. However, few investigations have been found focusing on the measurement study of internal mechanical performance which significantly influences the quality of printed products. In this study, several clay soil specimens with infill densities of 40%, 60%, 80%, and 100% were fabricated using AM method. Fiber Bragg grating (FBG) sensors were successfully mounted at the center of soil specimens (forming smart 3D printed clay soils) to monitor the horizontal strain distributions at different testing conditions. During AM process, lateral strain distributed at the horizontal center of all soil specimens presents linear rise as the increase of infill density from 40 to 100%. The strain values measured by FBG sensors are within a range between 22 and 210 με. In soil drying process, all strain values from FBG sensors present nonlinear decrease against time with a relatively stable residual level obtained at certain time after AM. The increase of infill density from 40 to 100% leads to a corresponding shrinkage strain up to a range from − 800 to 1400 με. In uniaxial loading tests, measured strains from FBG sensors present initial quick rise approaching two peak wavelength values. All measured strains at the center of soil specimens increase linearly as the increase of infill density values. Peak lateral strain almost doubled as the infill density increases from 40 to 100%. In this study, FBG sensor offers an effective monitoring method to investigate mechanical behavior of printed soils. [ABSTRACT FROM AUTHOR]

Soil is the most important source of K for plants; many studies have focused on soil K status and phytoavailability. However, there is still a lack of quantitative explanation for how soils hold plant‐available K. Based on the previous study, the ability to hold plant‐available K for soil was defined as soil potassium‐holding capacity (SKHC). Therefore, this study aimed to investigate the mechanisms underlying SKHC. Fourteen soils from different sites in China were collected and the contribution of soil organic matter (SOM) and clay minerals to SKHC were analyzed based on waterlogging simulation experiments, chemical determination, and data‐fitting analysis. Results showed that SKHC mainly depended on the absorption and holding effects of exchangeable sites deriving from both SOM and clay minerals (presented as cation exchange capacity [CEC]) and nonexchangeable sites deriving from clay minerals, which contributed 14.7 and 82.5%, respectively, to SKHC, at similar soil water‐soluble K levels. After removing the SOM from the soil, the average SOM and CEC decreased from 26.0 to 7.73 g kg–1 and from 13.7 to 11.8 cmol kg–1, respectively. The SOM contributed an average of 24.5% to CEC, with the remaining 75.5% provided by clay minerals. Further analysis showed when SOM increased by 1%, CEC increased by 1.14 cmol kg–1, a relative proportion of 8.32% of the initial soil. Therefore, SKHC is mainly determined by the nonexchangeable sites of soil clay minerals, and increasing CEC by improving SOM content to enhance SKHC should be an effective but slow approach. Core Ideas: The K in surface water above soil mainly comes from soluble‐ and exchangeable‐K.Nonexchangeable sites from soil clay dominate the soil potassium‐holding capacity.Exchangeable sites play a secondary role in soil potassium‐holding capacity.Increasing soil organic matter to elevate SKHC is effective but slow. [ABSTRACT FROM AUTHOR]

Expansive clay is one of the problems in construction work. The soil has the characteristics of being easy to expand when exposed to water, causing a decrease in the strength value of the soil. The can be overcome by stabilizing the soil. The soil is formed from weathering and contains the mineral montmorillonite. The soil is very sensitive to moisture content, has a high shrinkage rate, thus interfering in construction work. Therefore, additional materials are needed to overcome the problem, one of which is soil stabilization. The study aimed to stabilize the expansive clay soil. This is done by analyzing the physical and mechanical properties of expansive clay with a shell ash mixture. Expansive clay is taken directly (undisturbed) or disturbed. Undisturbed soil is taken using a tube, so that the soil is not disturbed by outside air, while disturbed soil is taken using a shovel and then put into a sack container. Expansive clay stabilization method lies in adding the percentage of shell ash mixture (5 %, 10 %, 15 %, and 20 %). The soil, the initial moisture content (γd) of which has been determined, is mixed, then molded into a cylindrical shape. The mold was stored in a desiccator, then watered with 5 % water every day until the soil became saturated. Then, using a Proctor test, chemical tests (soil chemical test, soil mineral test), physical tests (soil moisture, Atterberg limit), and mechanical tests (unconfined compression test, compaction test, swelling test) were carried out. The results showed that the addition of an oyster shell ash stabilizing agent to expansive clay affected the physical and mechanical properties of the soil. The addition of shell ash can reduce soil moisture with various plasticity indexes. While the soil stress value decreased, the swelling of the soil increased significantly above the original soil. [ABSTRACT FROM AUTHOR]

The fundamental mechanisms controlling shear strength and deformability behavior of clay-fiber mixtures have still not been well established, nor the constraints that may affect their performance of shearing under different drainage conditions. This study aims to understand the behavior of a clay soil mixed with polypropylene fibers using results from drained and undrained triaxial compression tests, and to provide necessary calibration data for a shear strength prediction model. In drained tests, shear strength increased with fiber inclusion for a given mean effective stress, represented by an increase in apparent cohesion. In the undrained tests, the shear strength was not affected by pore water pressure generation. Results from the drained and undrained tests indicate that the fiber content had a greater influence on the apparent cohesion than on the friction angle. Drainage affected the improvement in the peak shear strength of fiber-reinforced soils, with superior improvement in the drained tests. As the percent improvement in shear strength decreased with increasing effective confining stresses for both tests, the difference in behavior in the drained and undrained tests was attributed to the strain at failure, with failure occurring at large strains in the drained tests but at smaller strains in the undrained tests. • CD triaxial tests indicate that the fiber content had a greater influence on the apparent cohesion than on the friction angle. • Positive excess pore water pressures observed in all CU tests were not sensitive to the fiber reinforcement. • All the tests indicated a reduction in shear strength with fiber reinforcement with increasing effective confining stress. • Drainage affected the improvement in the shear strength (mostly peak strength) of fiber-reinforced soils in the drained tests. • Jamei et al. (2013) model adequately predicted the undrained shear strength of clay-fiber mixtures at low effective stresses. [ABSTRACT FROM AUTHOR]

Soil suction–based analyses are paramount to proper design of foundations in expansive soils, yet availability of field soil suction profiles from direct measurement is limited. A method was developed, using directly measured suction profiles obtained from sites across the US, by which routine geotechnical tests can be used to estimate soil suction to expand the database for estimation of field suction profiles. Herein, the expanded database is used to develop best-estimate clay soil suction envelopes for boundary conditions associated with covered or uncovered ground surface subjected to natural climatic surface flux. Where appropriate for site conditions, the proposed soil suction profile envelopes can be used with any suction-based heave/shrinkage analysis. Key features of the field suction envelopes, consistent with current popular approaches, include climate-dependent estimates for equilibrium suction at depth, depth to equilibrium (stable) suction, and variation in soil suction at the ground surface. Comparisons to existing soil suction envelope recommendations are made. Finally, a limited number of cases of developed/irrigated sites are presented for comparison to soil suction profiles obtained for natural climatic surface flux conditions. [ABSTRACT FROM AUTHOR]

Electrification is done in newer tractors hesitantly. There will be an increase in the need for electrified mounted implements and application units. Semi-liquid manure and degestate from biogas crops are increasingly injected directly into the soil. This technique reduces nutrient losses and ammonia emissions. In the case of loamy soils and clay, a high draft force is needed for slurry deposition into the soil. With the development and testing of an application unit with reduced working width of 3 m, the draft force reduction was found to be lower by nearly one third. The field trials have been performed in two steps: first, a prototype with spiked roller and star packer as a traction element on the roller unit in 3-m working width and second, a final slurry grubber with 6-m working width and cutting coulter on the traction roller. We tested both devices with and without powering the electrified traction roller. These field tests took place on six fields near Freising in Germany. Results showed that firstly, draft force reduction up to 35% was achieved with a powered traction roller on the mounted implement having 20% slippage on the traction roller. These values were obtained by pulling a tractor with the electrified implement by another tractor in a horizontal ground level. Second, we observed a different variation range of the values among the three test fields. This results from differences in the soil structure on the test fields having pebbles and stones near the soil surface or bigger stones down the working depth of 22.5 cm. The presented results show new kinds of working scenarios and operation modes for agriculture. Electrification can be an advantage in taking care of nutrient losses and ammonia emissions as it leads to a draft force reduction on heavy soils. [ABSTRACT FROM AUTHOR]

Soil compaction causes negative effects on crop yield and its mechanical response analysis has recently gained relevance for research through numerical methods. In this work, Finite Element Method (FEM) using the Mohr-Coulomb (MC) and Hardening Soil (HS) constitutive models were employed to simulate the mechanical response of a Vertisol agricultural soil. First, an experimental study of the unconsolidated-undrained (UU) triaxial compression test with different moisture contents (w = 10%, 20% and 34%) and confining pressures (σ3 = σc = 0.05 MPa, 0.10 MPa and 0.15 MPa) was carried out, to obtain the shear strength parameters cohesion (c) and friction angle (φ), as well as the Young's modulus (E) of the soil. The experimental study was conducted through a 32 factorial design with three replicates that it was used to evaluate the influence of the w and σc on E of the studied soil. Also, an analysis of the behavior of the φ and c parameters at each w was performed. Numerical simulations were done with similar conditions as the experimental tests with respect to loading and boundary conditions. A comparison of the mechanical response between numerical results and physical experiments was carried out. As a result, the MC model allowed to estimate satisfactorily the stress-strain relationship of the soil for w of 10% and 20%, while HS model exhibited a better approximation for w of 34% in comparison with the MC model. Finally, the methodology and the adjusted parameters of the agricultural soil obtained in this work, can be used in the study of soil compaction produced by the agricultural machinery. [ABSTRACT FROM AUTHOR]

Three extractions were used to assess the availability of micronutrients in different soil collections. The suitability of some extractions under the conditions of Egyptian soils will be discussed. Three extraction methods (Mehlic 3, Soltanpour and Kelowna) were used for the determination of available Fe, Zn, Mn, Cu and B content of the soil samples (sand, calcareous and clay) during 2020 season. Surface soil samples (0-30 cm) were collected from three sites of Al Boston area in the new Nobaria, Governorate, Egypt, during 2020 season. From each selected plot, ten points were selected in a zig-zag path. The results revealed that the highest values of available Fe, Zn and Cu were given with the extraction solution of Soltanpour, while the highest values of available Mn and B were given with the extraction solution of Mehlic 3. On the other hand, the results showed that clay soil recorded the maximum available Fe, Zn, Mn and Cu, while calcareous soil recorded the maximum available boron content. The interaction between different extraction methods and soil samples was highly significant during 2020 season. [ABSTRACT FROM AUTHOR]

Determining a specific site 's geotechnical parameters is a crucial step in geotechnical analyses and designs in a seismically active area. In recent years, many parts of Nigeria have been subjected to several earthquakes; therefore, subsurface description has been a challenging task in geotechnical practice in this region. This paper aims to evaluate subsurface formation for soil liquefaction analysis at a sugar plant site located in Nigeria 's Upper Benue region. The study used data from the standard penetration test (SPT) measured at 28 boreholes and soil samples ' laboratory analysis. The liquefaction parameters were derived according to the procedure in Idriss and Boulanger (2014). Soil liquefaction has been evaluated, assuming an earthquake scenario of 7.5 Mw with a peak horizontal acceleration (amax) of 0.15 g. Results showed that the subsurface formation between 1.5 and 4.5 m is saturated loose to medium-dense sandy, silty clayey soil, and the liquefaction safety factor is less than 1. The Formation at a depth deeper than 4.5 m comprises very densely to stiff clayey sands with a safety factor higher than 1. The applied approach has been proved to be a rapid and reliable method for investigating sandy soil's liquefaction under the effect of earthquakes. [ABSTRACT FROM AUTHOR]

• A single-reading hydrometer method developed for rapid determination of soil texture. • Bouyoucos' method was not accurate method to determine clay H (H = hydrometer) content. • High correlation was obtained between clay P (P = pipette) and clay H (r = 0.987). • A single-reading of hydrometer at 6 h (P 6) was a good proxy for clay H content. • The P 6 -function excellently predicted clay H content (validation dataset r 2 = 0.985). Standard hydrometer procedure is labor-intensive and time-consuming. We aimed to 1) test how fraction of soil clay-sized particles (clay H) can be estimated using only a single-reading at time t in the hydrometer method, and 2) develop predictive functions to estimate clay H fraction using the particles fraction obtained from hydrometer reading at time t (P t). Particle size distribution (PSD) of samples from 246 Iranian and 61 Belgian soils were determined by the hydrometer method. In addition, the PSD of the 61 Belgian soil samples were determined by the pipette method. Finally, the measured clay H based on the standard procedure of hydrometer was estimated by P t values at times 1, 3, 6, and 24 h using regression analysis. High positive-correlation (correlation coefficient, r = 0.987) was observed between clay H and that of obtained from pipette method. Particle fraction obtained from hydrometer reading at time 6 h (P 6) resulted in the highest correlation with clay H. Among the developed P t -functions, the P 6 -function (Cla y H = 0.965 P 6 - 1.12) represented the highest capability to estimate clay H (coefficient of determination, r 2, of 0.992 and 0.985 for calibration and validation datasets, respectively). The absolute values of clay H were close to that of P 6. However, it is strongly recommended to use P 6 -function to acceptably estimate Clay H , particularly in silty soils. Although the suggested procedure is simple, it is as reliable as the standard hydrometer method for determining the soil clay H content. [ABSTRACT FROM AUTHOR]