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To study how the soils, respond to an earthquake, seismic waves are frequently utilized. The purpose of this work is to build the porosity graphs based on the geotechnical parameters of the soils and forecast the porosity of shallow clay soils using seismic wave velocities that analyze the dynamic features of the soil. Compressional (P) and shear (S) wave velocities, seismic velocity ratio, Poisson ratio, bulk modulus, and shear modulus are the factors used to calculate porosity. In this work, porosity values are calculated using grain and dry densities of core samples taken from different boreholes within the study region, and bulk modulus, shear modulus, and Poisson ratio are calculated using P- and S-wave velocities obtained by utilizing the seismic-refraction method, as well as porosity values. The research region is in Iran; Isfahan Metro Line 2 and mostly consists of clay, silt, sand, and gravel deposits. Based on the values of the Poisson ratio, seismic P-wave velocity, seismic velocity ratio (Vp/Vs), and the stiffness of the clay soils, the data of the clay soils in the region were individually sorted. These characteristics were used to create novel multi-parameter relationships between clay soil porosity, seismic velocities, shear modulus, and the Poisson ratio. Using the error norm approach, the errors in the parameters utilized for each relationship were identified. The error norm technique's findings show that the shear wave velocity and shear module have the lowest error when calculating porosity. Therefore, it is advised to estimate porosity of shallow clay soils using the given correlations. These relationships can be used to assess the porosity of clay soil and to determine if the soil's pores are saturated with liquid. [ABSTRACT FROM AUTHOR]

Clayey soils present challenges in engineering applications due to their inherent properties, such as low shear strength, which usually limits their use in engineering applications. Stabilization of clayey soils is crucial to enhance their performance and suitability for various purposes. Utilizing waste materials like discarded tyres and tile powder as soil stabilizers presents a sustainable solution to mitigate environmental concerns while enhancing soil properties. While previous studies have explored using either crumbled rubber or tile powder independently for soil improvement, their combined effect remained largely unexplored. This study addresses this gap by investigating the synergistic potential of blending crumbled rubber and tile powder to enhance the strength and ductility of clayey soils. A series of laboratory tests were conducted to investigate the combined effect of crumbled rubber and tile powder. First, varying percentages of crumbled rubber (2.5%, 5.0%, 7.5%, and 10%) were mixed with the soil, and standard proctor tests, California bearing ratio (CBR) tests, and unconfined compressive strength (UCS) tests were performed. Results showed optimal performance at 5.0% crumbled rubber, exhibiting the highest values for maximum dry density, CBR, and UCS. Subsequently, different percentages of tile powder (5%, 10%, 15%, and 20%) were added to the soil-rubber mixture (with 5% crumbled rubber). The addition of 15% tile powder to the 5% crumbled rubber mixture yielded the most significant improvements as maximum dry density (MDD) increased from 1.842 g/cm3 (raw soil) to 1.963 g/cm3, UCS increased from 0.5176 kg/cm2 (raw soil) to 2.606 kg/cm2, and CBR increased from 1.757% (raw soil) to 7.84%. The addition of crumbled rubber was found to shift the failure behaviour of the clayey soil from brittle to more ductile, indicating an enhanced ability to undergo deformation before failure. This study's findings highlight the potential of combining crumbled rubber and tile powder as a sustainable solution for enhancing clayey soil properties, paving the way for further research into optimized mixture designs and expanded applications in geotechnical engineering. [ABSTRACT FROM AUTHOR]

The practise of geophagy is common amongst women of childbearing age from different geographic locations, including South Africa, regardless of their social and economic status such as their level of education, race, marital status, income or occupation. This study aimed to examine the women of childbearing age in Tshwane District, Gauteng Province, South Africa. An experimental study was conducted at the laboratory to examine the chemical composition of clay soil ingested by geophagic women of childbearing age. Thirty-nine clay soil samples were collected from study participants attending antenatal care services and family planning at public healthcare facilities of Tshwane District, Gauteng Province, and subjected to geochemical analysis. The concentrations of vanadium, manganese, chromium, and barium were detected in quantities exceeding 100 mg/kg in almost all samples. Cadmium, mercury and silver were detected in low concentrations below 1 mg/kg in all samples. The practice of geophagy amongst women of childbearing age has been reported to be associated with detrimental health outcomes and risks such as iron deficiency anaemia, constipation, shortness of breath, maternal and childhood mortalities and morbidities, neurological and central nervous system disorder, death, appendicitis, cancers, teratogenic risks, and ulcers. The chemical composition of clay soil eaten by geophagic women of childbearing age contains potentially harmful substances, thus the practise of geophagy is toxic and should be discouraged to protect public health. [ABSTRACT FROM AUTHOR]

Abstract Clayey soils present challenges in engineering applications due to their inherent properties, such as low shear strength, which usually limits their use in engineering applications. Stabilization of clayey soils is crucial to enhance their performance and suitability for various purposes. Utilizing waste materials like discarded tyres and tile powder as soil stabilizers presents a sustainable solution to mitigate environmental concerns while enhancing soil properties. While previous studies have explored using either crumbled rubber or tile powder independently for soil improvement, their combined effect remained largely unexplored. This study addresses this gap by investigating the synergistic potential of blending crumbled rubber and tile powder to enhance the strength and ductility of clayey soils. A series of laboratory tests were conducted to investigate the combined effect of crumbled rubber and tile powder. First, varying percentages of crumbled rubber (2.5%, 5.0%, 7.5%, and 10%) were mixed with the soil, and standard proctor tests, California bearing ratio (CBR) tests, and unconfined compressive strength (UCS) tests were performed. Results showed optimal performance at 5.0% crumbled rubber, exhibiting the highest values for maximum dry density, CBR, and UCS. Subsequently, different percentages of tile powder (5%, 10%, 15%, and 20%) were added to the soil-rubber mixture (with 5% crumbled rubber). The addition of 15% tile powder to the 5% crumbled rubber mixture yielded the most significant improvements as maximum dry density (MDD) increased from 1.842 g/cm3 (raw soil) to 1.963 g/cm3, UCS increased from 0.5176 kg/cm2 (raw soil) to 2.606 kg/cm2, and CBR increased from 1.757% (raw soil) to 7.84%. The addition of crumbled rubber was found to shift the failure behaviour of the clayey soil from brittle to more ductile, indicating an enhanced ability to undergo deformation before failure. This study’s findings highlight the potential of combining crumbled rubber and tile powder as a sustainable solution for enhancing clayey soil properties, paving the way for further research into optimized mixture designs and expanded applications in geotechnical engineering.

Introduction. Determination of strength and deformation characteristics of soils composing the soil mass is the key process of calculation and design of structures of all types. High accuracy in determining mechanical characteristics plays a huge role at every stage of project development. Triaxial compression units are one of the most popular and widely used devices for laboratory research, as this type of testing allows you to reproduce the stress-strain state of the soil mass and determine its mechanical characteristics most accurately.Materials and methods. Experimental studies were performed on clay soil specimens (sandy loam, loam, clay) in a triaxial compression device in a consolidated-drained mode in order to study the effect of the coefficient of non-uniformity of expansion of the soil specimen on its mechanical properties.Results. Analyzing the data of experimental studies, it was found that the coefficient of non-uniformity of expansion of specimen b has a significant effect on the obtained values of the mechanical characteristics of clay soil, namely: the values of the angle of internal friction in the medium increased by 5 %; the values of specific adhesion increased by 4.4 % on average. However, it should be noted that despite the increase in the strength characteristics of the tested soil specimens, the exclusion of the coefficient b from the treatment process led to a decrease in the values of the secant deformation modulus at 50 % strength E50 by an average of 4.5 %.Conclusions. The obtained overestimated values of strength characteristics φ, c and underestimated values of deformation characteristics E50 are not critical, however, to increase the accuracy of calculations performed based on the results obtained as a result of in-house processing of laboratory test specimens, the coefficient of uneven expansion b of the specimen should be taken into account.

Introduction. Clay soil is a multiphase, multicomponent aluminosilicate dispersed system with specific properties determined not only by its composition but also by the formation of coagulative and transition contacts (binds) between the soil particles. One of the methods of changing soil properties is the introduction of active mineral additives that promote the formation of phase contacts (binds) between soil particles as a result of the pozzolanic reaction. The effectiveness of using carbide sludge, which is a multi-tonnage lime-containing waste (the content of active calcium oxide reaches 56%) as an additive, has been proved. However, to date, the proposed mechanism of interaction in the «clay soil – carbide sludge» system is based only on the literature data and has not been experimentally verified. The purpose of this research is to study the mechanism of structure formation in the «clay soil – carbide sludge» dispersed system. Methods and materials. A soil model has been created by mixing saponite-containing material with sand, which corresponds to the composition and properties of sandy loam. The carbide sludge in the form of a suspension was selected from the sludge collector, dried to a constant mass and sieved. Microstructural analysis, differential thermal analysis (DTA), and X-ray phase analysis were used to study the mechanism of structure formation. Results and discussions. Based the results of the differential thermal analysis, there is a decrease in the intensity of the endothermic effect in the range of 460 to 470°C associated with the decomposition of calcium hydroxide in the treated sample. Additionally, an endothermic effect is observed at 750°C, which indicating the decomposition of calcium silicate hydrate. The results of differential thermal analysis are confirmed by X-ray phase analysis, which shows the presence of tobermorite group hydrosilicates in the reaction medium. The study of the microstructure of the analyzed mixtures revealed a decrease in the specific volume of pores with a diameter of 4–5 nm in the modified clay soil. This is associated with gelling from particles of new hydrate formations. Besides that, the volume of pores with a diameter of more than 6 nm increased, which indicates the process of

Depending on the texture of soil, different physicochemical and microbiological parameters are characterized, and these characteristics are influenced by crop cultivation. Stevia, a popular zero-calorie sweetener crop, is widely cultivated around the world on various soil textures. Sandy loam and clay soil show great differences in physicochemical and biological parameters and are often used for Stevia cultivation. To understand the effects of Stevia cultivation on soil physicochemical and biological features, we investigated the changes of physicochemical and microbiological parameters in sandy loam and clay soil following Stevia cultivation. This study was carried out through different physiological and biochemical assays and microbiomic analysis. The results indicated that the sandy loam soil had significantly lower pH and higher nutrient content in the rhizosphere and bulk soils after the Stevia cultivation. The sandy loam soil maintained higher bacterial diversity and richness than the clay soil after Stevia harvest. Beneficial bacteria such as Dongia, SWB02, Chryseolinea, Bryobacter and Devosia were enriched in the sandy loam soil; however, bacteria such as RB41, Haliangium and Ramlibacter, which are unfavorable for nutrient accumulation, predominated in clay soil. Redundancy analysis indicated that the variation in the composition of bacterial community was mainly driven by soil pH, organic matter, total nitrogen, available phosphorus, and microbial biomass phosphorus. This study provides a deeper understanding of physicochemical and microbiological changes in different soil textures after Stevia cultivation and guidance on fertilizer management for Stevia rotational cultivation. [ABSTRACT FROM AUTHOR]

Due to the high rate of the development of housing, transportation and hydraulic engineering construction in the last hundred years, the study of the phenomenon of creep of clay soils has become a subject of scientific research. In the study, experimental investigations of clay soil were conducted using a simple shear device in kinematic loading mode, aimed at examining the influence of shear rate on the viscosity coefficient of the clay soil and its strength characteristics. The tests were performed at four different shear rates and three different vertical load values. Based on the results of experimental and theoretical studies, the viscosity coefficients of clay soil were obtained, and a new rheological equation was proposed, which simultaneously takes into account the influence of Coulomb friction, structural cohesion, cohesion of water–colloidal bonds and viscous resistance of the soil. It has been shown that the shear rate has a significant impact on the viscosity coefficient of clay soil, and the viscosity coefficient itself is a variable quantity, depending both on the magnitude of the applied load and the duration of its application. The obtained results can be used for further improvement of methods for calculating the settlement of structures over time, as well as for predicting the time until the bearing capacity of foundation soils is exhausted. [ABSTRACT FROM AUTHOR]

Soil enzymes play a critical role in the biogeochemical cycles of essential nutrients and protect soil against the accumulation of harmful organic compounds. However, there is limited information on the effect of pesticides on enzyme activities in both old and newly reclaimed Egyptian soils. Laboratory studies were conducted to determine the effects of two nematicides (carbofuran and oxamyl) and two herbicides (ametryn and bentazone) on dehydrogenase and phosphatase activities in alluvial soil (clay soil) and calcareous soil (sandy soil) at concentrations of 25 and 100 µg/g soil over eight weeks. The results showed that dehydrogenase and phosphatase activities were generally enhanced in both clay and sandy soils treated with all tested pesticides. However, oxamyl had the lowest effect on dehydrogenase and phosphatase activities in both soil types compared to the other pesticides used in this study. Dehydrogenase and phosphatase activities in treated or untreated clay soil were higher than those in sandy soil. Additionally, the highest enhancement of dehydrogenase activity was observed at low concentrations of carbofuran and oxamyl, while a high concentration of ametryn and bentazone had a similar effect in both soil types. The highest stimulation of phosphatase activity was achieved at low pesticide concentration in clay soil, whereas high concentration was more effective in sandy soil. Based on the results obtained, it can be stated that the pesticide concentration, the soil type, and the incubation time are important factors affecting the pesticide-soil enzyme relationship. Accordingly, such a study can be used, which indicates the induction of such important enzymes in the soil, which can be used as an indicator to measure pesticide contamination in the soil within 60 days of exposure to pesticides. [ABSTRACT FROM AUTHOR]

Sepiolite is a fibrous clay mineral, which is mostly associated with a semi-arid to arid climate, with characteristics intermediate between kaolinite and montmorillonite minerals. An experimental study was conducted, with the goal of creating a substantial database of physical, microstructural, and geotechnical characteristics of sepiolite to develop its applications as a natural resource that is explored as the main deposit of Iran. It has been found that sepiolite soils were lightweight, porous, and cohesive with negligible settlement and swelling properties and almost high UCS values. Various analysis were performed to characterise the macroscopic behaviour (Atterberg limit, physical, and compressibility tests), microstructural, chemical, and mineralogical characterisations by chemical analysis, X-Ray diffraction, and Scanning Electron Microscopy. At first glance, sepiolite soils showed high liquid limits with medium to high plastic indices which can result in problems including creation of up and down movements in foundations. After mixing with silt and fine sand to decrease high liquid limit and optimum moisture amounts, sepiolite is suitable candidate for engineering applications (including clay liners, clay cores, etc.) due to its compressibility and strength characteristics. In conclusion, sepiolite soils are strongly recommended for geo-environmental structures due to their adsorption capacity, low permeability coefficient, and suitable strengths. [ABSTRACT FROM AUTHOR]

Soft to medium clay soil possesses major sources of damages to the pavement layers overlying them because of their potential failure under moisture changes and external heavy traffic load. In such situations, soil stabilization methods can be used to improve the soil properties and satisfy the desired engineering requirements. This study presents the use of sugarcane bagasse ash (SBA) and lime as chemical stabilizers for a clay soil subbase. Sugarcane bagasse ash and lime are used individually and as mixtures at varying percentages to stabilize a clay soil from Taxila, Pakistan. Various geotechnical laboratory tests such as Atterberg limits, compaction test, and California Bearing Ratio (CBR) are carried out on both pure and stabilized soils. These tests are performed at 2.5%, 5%, and 7.5% of either SBA or lime by weight of dry soil. In addition, mixtures of lime and SBA in ratios of 1:1, 2:1, 3:1, 1:2, and 1:3 are used in 5%, 7.5%, and 10% of dry soil weight, respectively. Results indicate that soil improved with 7.5% SBA showed a 28% increase in the liquid limit, while soil mixed with 2.5% lime in combination with 7.5% SBA showed an increase of 40% in the plastic limit. For the plasticity index, the soil mixed with 7.5% SBA showed an increase of 42%. Moreover, 2.5% lime in combination with 2.5% SBA showed the best improvement in soil consistency as this mixture reduced the soil plasticity from high to low according to the plasticity chart. Furthermore, 2.5% SBA in combination with 5% lime demonstrated the largest improvement on the CBR value, which is about a 69% increase above that of the pure soil. Finally, the cost analysis indicates a promising improvement method that reduces pavement cost, increases design life, and mitigates issues of energy consumption and pollution related to SBA as a solid waste material. [ABSTRACT FROM AUTHOR]

The geotechnical properties of clay soil and its mixtures with different proportions (0.75%, 0.85%, 1%, and 1.15%) of Agar Gum biopolymer and Ferrochromium Slag (0.25%, 0.50%, 0.75%, and 1%), having various curing times and freeze-thaw cycles, were studied through a series of soil mechanical tests to investigate possibilities to improve its undesired/problematic plasticity, compaction, and shear strength characteristics. The results revealed that treatment with an optimal ratio of 1% Agar Gum and 1% Ferrochromium Slag alone, as well as together with, improved the geotechnical properties of the clay soil considerably. Both the unconfined and shear strength properties, along with the cohesion and internal friction angle, increased as much as 47 to 173%, depending on the curing time. The higher the curing time, the higher the shear strength, cohesion, and internal friction angle are up to 21 days. Deteriorating the soil structure and/or fabric, freeze-thaw cycles, however, seem to have an adverse effect on the strength. The higher the freeze-thaw cycle, the lower the shear strength, cohesion, and internal friction angle. Also, some improvements in the plasticity and compaction properties were determined, and environmental concerns regarding Ferrochromium Slag usage have been addressed. [ABSTRACT FROM AUTHOR]

Construction of earth fill dams offers a cost-effective solution for various purposes. However, their susceptibility to internal soil erosion, known as piping, poses a significant risk of structural failure and resultant loss of life and property. Soil stabilization emerges as a practical technique to fortify these dams against such threats. This study investigated the impact of lime on the internal erosion properties of clay soils, focusing on CH and ML soil types. Specimens of different lime content were prepared and remolded at 95% relative compaction and optimum moisture content. Hole Erosion tests at varying lime concentrations and curing durations were adapted to conduct the investigation. This investigation aims to optimize lime content and curing time for cohesive soil stabilization against internal erosion. Findings revealed that 2% and 5% of quicklime, by dry weight of the soil, effectively stabilized CH and ML soils, respectively, against internal erosion, with a two-day curing period proving optimal. Furthermore, the addition of lime significantly enhanced erosion rate index and critical shear strength in clay soil, underscoring its efficacy in soil stabilization efforts. [ABSTRACT FROM AUTHOR]

Depending on the texture of soil, different physicochemical and microbiological parameters are characterized, and these characteristics are influenced by crop cultivation. Stevia, a popular zero-calorie sweetener crop, is widely cultivated around the world on various soil textures. Sandy loam and clay soil show great differences in physicochemical and biological parameters and are often used for Stevia cultivation. To understand the effects of Stevia cultivation on soil physicochemical and biological features, we investigated the changes of physicochemical and microbiological parameters in sandy loam and clay soil following Stevia cultivation. This study was carried out through different physiological and biochemical assays and microbiomic analysis. The results indicated that the sandy loam soil had significantly lower pH and higher nutrient content in the rhizosphere and bulk soils after the Stevia cultivation. The sandy loam soil maintained higher bacterial diversity and richness than the clay soil after Stevia harvest. Beneficial bacteria such as Dongia, SWB02, Chryseolinea, Bryobacter and Devosia were enriched in the sandy loam soil; however, bacteria such as RB41, Haliangium and Ramlibacter, which are unfavorable for nutrient accumulation, predominated in clay soil. Redundancy analysis indicated that the variation in the composition of bacterial community was mainly driven by soil pH, organic matter, total nitrogen, available phosphorus, and microbial biomass phosphorus. This study provides a deeper understanding of physicochemical and microbiological changes in different soil textures after Stevia cultivation and guidance on fertilizer management for Stevia rotational cultivation.

Utilizing the aggregate piers is one of the methods to improve and increase the bearing capacity of soft soils. The ultimate bearing capacity of these piers is affected by parameters such as the physical properties of the piers, structural conditions, the embedment depth and replacement ratio of piers, which complicates the estimation of bearing capacity. In this study, the Gene Expression Programming method was used for the prediction of the ultimate bearing capacity of clay soils reinforced with aggregate piers. For this purpose, two different models were developed, of which the first model (GEP2) utilized two input variables, the undrained shear strength of clay (Su) and replacement ratio (ar), while the second model (GEP4) used four input variables including the undrained shear strength of clay (Su), replacement ratio (ar), slenderness ratio (Sr), and embedment depth of piers (df). The coefficient of determination of the GEP2 model, and the GEP4 model is 0.921 and 0.942, respectively. Besides, comparing the GEP4 model of this research with the developed models of previous studies confirms the superior performance of the GEP4 model, considering both the accuracy and number of input parameters. The results of sensitivity analysis showed that the undrained shear strength of clay (Su), replacement ratio (ar), slenderness ratio (Sr), and embedment depth of piers (df) have the highest impact on the prediction of bearing capacity, respectively. Furthermore, the parametric analysis demonstrated that increasing the Su, ar, Sr, and df would improve the bearing capacity of the aggregate piers reinforced clay.

The practise of geophagy is common amongst women of childbearing age from different geographic locations, including South Africa, regardless of their social and economic status such as their level of education, race, marital status, income or occupation. This study aimed to examine the women of childbearing age in Tshwane District, Gauteng Province, South Africa. An experimental study was conducted at the laboratory to examine the chemical composition of clay soil ingested by geophagic women of childbearing age. Thirty-nine clay soil samples were collected from study participants attending antenatal care services and family planning at public healthcare facilities of Tshwane District, Gauteng Province, and subjected to geochemical analysis. The concentrations of vanadium, manganese, chromium, and barium were detected in quantities exceeding 100 mg/kg in almost all samples. Cadmium, mercury and silver were detected in low concentrations below 1 mg/kg in all samples. The practice of geophagy amongst women of childbearing age has been reported to be associated with detrimental health outcomes and risks such as iron deficiency anaemia, constipation, shortness of breath, maternal and childhood mortalities and morbidities, neurological and central nervous system disorder, death, appendicitis, cancers, teratogenic risks, and ulcers. The chemical composition of clay soil eaten by geophagic women of childbearing age contains potentially harmful substances, thus the practise of geophagy is toxic and should be discouraged to protect public health.

This paper presents an experimental study that aims to enhance the cracking resistance of clay soil. Laboratory tests were performed in order to assess the effect of fiber content and length on the desiccation cracking of clay soil. During these tests, a digital image acquisition system was used to depict the development and spread of cracks. The results were analyzed using the DIC digital image correlation technique for the full-strain obtaining and image processing analysis for the crack feature measurements. The results show that date palm fibers have a considerable impact on the wide spread of cracks in clay soil during desiccation, in addition to their area and width. The DIC approach was useful for monitoring the displacement evolution and strain field detection on the surface of the specimen. The addition of fibers slows the water evaporation rate of the specimens. Optimum crack reduction ratio of about 47% was found in fiber-reinforced clay with 0.75% fiber content at 10 mm fiber length. [ABSTRACT FROM AUTHOR]

Utilizing the aggregate piers is one of the methods to improve and increase the bearing capacity of soft soils. The ultimate bearing capacity of these piers is affected by parameters such as the physical properties of the piers, structural conditions, the embedment depth and replacement ratio of piers, which complicates the estimation of bearing capacity. In this study, the Gene Expression Programming method was used for the prediction of the ultimate bearing capacity of clay soils reinforced with aggregate piers. For this purpose, two different models were developed, of which the first model (GEP2) utilized two input variables, the undrained shear strength of clay (Su) and replacement ratio (ar), while the second model (GEP4) used four input variables including the undrained shear strength of clay (Su), replacement ratio (ar), slenderness ratio (Sr), and embedment depth of piers (df). The coefficient of determination of the GEP2 model, and the GEP4 model is 0.921 and 0.942, respectively. Besides, comparing the GEP4 model of this research with the developed models of previous studies confirms the superior performance of the GEP4 model, considering both the accuracy and number of input parameters. The results of sensitivity analysis showed that the undrained shear strength of clay (Su), replacement ratio (ar), slenderness ratio (Sr), and embedment depth of piers (df) have the highest impact on the prediction of bearing capacity, respectively. Furthermore, the parametric analysis demonstrated that increasing the Su, ar, Sr, and df would improve the bearing capacity of the aggregate piers reinforced clay. [ABSTRACT FROM AUTHOR]

Soil contamination with medicines can occur when unused or expired medications are improperly disposed of or when pharmaceutical manufacturing waste is inadequately treated or managed. Moreover, the largest percentage of damaged and expired medical materials in the sanitary landfill area during the COVID-19 period in the study region were Metronidazole (Flagyl) and Amoxicillin. The disposal of numerous drugs and medical waste from Al-Jazeera Pharmaceuticals Company, which were examined and found to have a higher concentration of the compound Metronidazole (Flagyl) and Amoxicillin, This study aimed to analyze the results of the impact of Metronidazole (Flagyl) and Amoxicillin concentrations on the chemical and geotechnical properties of soil. Undisturbed soil samples was collected and then cured by mixing 10 mg/l of Metronidazole (Flagyl) and 25 mg/l of Amoxicillin to the time period from 15 to 135 days. The obtained geotechnical tests results of natural and contaminated silty clay soil showed that the soil became softer, the cohesiveness between the particle sizes of soil decreased due to the absorption of the soil by the Metronidazole (Flagyl) and Amoxicillin concentration. Moreover, the results indicate that the soil collapse rose from 5.6 to 9.5 after 150 days of curing. [ABSTRACT FROM AUTHOR]

The stabilization of a clay soil contaminated with glycerol was studied through a series of experimental tests. Contaminated soil was artificially prepared with percentages of 4,8 and 12% from the solution of glycerol with concentration of 50%. GGBS and activated GGBS with MgO or mixture of MgO and cement were used as agent materials. They were added and mixed with both natural and contaminated soil at percentages of 5,10 and 15%. Atterberg limits, compaction and unconfined strength tests (UCS) were performed on both soils with and without agents. The results showed that these parameters varied when adding glycerol or different agents and the extent of these changes were dependent on the percentage of glycerol and the type of agent. In addition, it was resulted that under constant conditions, strength values were dependent on the curing time. E50 (Elastic coefficient) for each strength test was calculated and the variations in its value corresponded to changes in strength. Comparing the results indicated that the effect of activated GGBS in increasing the strength and E50 of both soils were greater than that of GGBS alone. Based on the SEM results, it was revealed that the increase in the strength of stabilized soil is due to the production of chemical bonds between the particles of soil. [ABSTRACT FROM AUTHOR]

This study aims to evaluate the performance of light clay soil amended with inorganic fertilizer in the early cashew seedling growth phase. The two month experiment was set up in a screenhouse at the Cocoa Research Institute of Nigeria. The experiment was laid out in Complete Randomized Design. The first factor consists of cashew biotypes (large and medium) while the second factor includes 2 fertilizer combinations (Urea and Single-Super-Phosphate (SSP)). The treatments include Large + 0 (L0 as control), Large + 40kg/ha Urea + 30kg/ha SSP (L1), Large + 80kg/ha Urea + 60kg/ha SSP (L2), Medium + 0 (M0 as control), Medium + 40kg/ha Urea + 30kg/ha SSP (M1), and Medium + 80kg/ha Urea + 60kg/ha SSP (M2). We applied the treatments one month after sowing. One nut seed per nursery polythene bag was sown using a light clay soil growing medium. The physicochemical properties of the growing media were analyzed while data on seedling emergence, growth parameters, and % seedling survival were recorded. Data was analyzed using Analysis of Variance, and treatment means were separated using Duncan Multiple Range Test (DMRT) at 0.05% probability level. Seedlings with no fertilizer treatments, L0 (4.5) and M0 (4.0), had the best seedling vigour, while L2 (2.5) and M2 (2.0) had the lowest, respectively, in a 5-grade score. The control, jumbo, and medium biotypes recorded a survival rate of 100%, 33.33%, and 16.67%, respectively. The application of the inorganic fertilizers to the light clay soil used negatively influenced cashew seedling growth. [ABSTRACT FROM AUTHOR]

Co-application of fertilisers and biofertilisers increases solubility and concentration of nutrient elements in the soil. However, information on the effect of P fertiliser and rhizobium inoculation on the concentration of mineral elements in the rhizosphere of field-grown chickpea in contrasting soil types is lacking. We assessed the effect of phosphorus fertiliser, rhizobium inoculation, and rhizobium inoculation plus P fertilizer on the concentration of nutrients in the rhizosphere of 2 chickpea genotypes (ACC#1 & ACC#5) at clay and sandy soil sites in two consecutive years. ACC#5 accumulated higher amounts of rhizospheric nutrients than ACC#1 in both soil types despite the variable response to fertiliser treatment. Rhizobium inoculation plus P fertiliser resulted in higher accumulations of rhizosphere N (7-219%), P (20-348%), K (9-365%), Ca (2-155%) and Zn (15-259%) compared to the other fertiliser treatments suggesting an additive effect of P fertiliser and rhizobium inoculation. Moreover, the effect of fertiliser treatments was more pronounced in the clay than the sandy soil. Our investigation is the first to document the effects of fertiliser treatment, genotype, and soil type on the accumulation of rhizosphere nutrients in field-grown chickpea. However, we propose further studies, incorporating more cultivars and environments, before making practical recommendations.

Fiber-reinforced soils have been increasingly used in geotechnical engineering. Over the years, research has sought to understand and investigate the influences of fibers as reinforcement in soil–fiber mixtures. This study assessed the behavior of clayey soil in the city of Curitiba (Paraná, Brazil), adding rice husk fiber (RHF), an industrial waste from Cooperativa Agroindustrial in Alegrete (Rio Grande do Sul, Brazil). To evaluate the effect of the presence of natural RHF on the mechanical behavior of compacted soil, aspects such as the influence of fiber content and the drained and undrained behaviors of the soil were evaluated through unconfined triaxial compression tests. The following tests were realized: soil granulometry, specific mass of solids and Atterberg limits. Specimens were produced in quadruplicate for the soil and mixtures using the RHF contents of 0.5%, 0.75%, 1% and 1.5% to determine the unconfined compressive strength (UCS). Triaxial tests were realized on a pure soil specimen and the specimens with 1% RHF under confining pressures of 50 kPa, 100 kPa, 200 kPa and 400 kPa. The interactions at the interface between husk surface and soil were analyzed using scanning electron microscopy (SEM). In UCS tests, specimens with RHF percentages of 1% and 1.5% presented the highest results, with an increment of 36% compared to the soil without RHF. The results of the consolidated drained triaxial compression tests show that in terms of effective stress, there was a small difference in the strength of the compacted pure soil and soil with the addition of RHF. For the undrained tests, the strength increased with the inclusion of husk, with a reduction of 50% in cohesion and an increment of 22% in friction angle for specimens containing RHF compared to the soil without RHF additions.

Due to the high rate of the development of housing, transportation and hydraulic engineering construction in the last hundred years, the study of the phenomenon of creep of clay soils has become a subject of scientific research. In the study, experimental investigations of clay soil were conducted using a simple shear device in kinematic loading mode, aimed at examining the influence of shear rate on the viscosity coefficient of the clay soil and its strength characteristics. The tests were performed at four different shear rates and three different vertical load values. Based on the results of experimental and theoretical studies, the viscosity coefficients of clay soil were obtained, and a new rheological equation was proposed, which simultaneously takes into account the influence of Coulomb friction, structural cohesion, cohesion of water–colloidal bonds and viscous resistance of the soil. It has been shown that the shear rate has a significant impact on the viscosity coefficient of clay soil, and the viscosity coefficient itself is a variable quantity, depending both on the magnitude of the applied load and the duration of its application. The obtained results can be used for further improvement of methods for calculating the settlement of structures over time, as well as for predicting the time until the bearing capacity of foundation soils is exhausted.

ABSTRACT: Introduction. Pozzolatic activity is an important indicator for highly dispersed materials, particularly clay soils. It determines their effective use and characterizes the ability of the active components in their composition to interact with calcium hydroxide. Various methods are employed to assess this pozzolatic activity. Potentiometric methods are effective. They are based on measuring the electrode potential, which is functionally related to the change in the concentration (activity) of calcium ions in the analyzed solutions as the main information parameter of the pozzolatic reaction. The purpose of the research is to test the potentiometric method to assess the pozzolatic activity of highly dispersed materials, as well as the application of suggested approach to determine the rational amount of an active mineral lime-containing additive as a binder component for producing soil-concrete. Materials and Methods. We have chosen clay soil models with different plasticity index and sandy loam of the Arkhangelsk region as the objects. The potentiometric analysis method involved sequentially adding 0.015 mol/l calcium hydroxide solution, in amounts ranging from 0.2 to 0.8 ml, to a suspension containing 0.5 g of soil in 80 ml of distilled water. The potential of the system was measured while continuously stirring at a fixed speed. Results and Discussion. All studied objects are characterized by the pozzolatic activity, which increases in the series sandy loam sandy → clay loam light silty → clay light silty ≈ sandy loam silty and has the order of absolute values coinciding with the literature data. The rational amount of the active mineral lime-containing additive was 1–2% for clay soil models, depending on the plasticity index, and more than 2 % for the sandy loam of the Arkhangelsk region (from the soil mass on dried basis). Conclusion. We have shown the applicability of the potentiometric method of analysis using a calcium-selective electrode to assess the pozzolatic activity of highly dispersed materials on the example of models of clay soils with different plasticity index and sandy loam of the Arkhangelsk region

Granular pile is one of the proven soil improvement mechanisms applied especially for reinforcement of compressible soils supporting light structures. The improvement performance of granular piles is influenced by various factors including the dimension parameters (length, spacing and diameter of the piles). The influence of these three dimension parameters on deformation response of reinforced weak soil has widely been reported. However, the most influential parameter affecting deformation of the weak soil has not been clearly identified. Apparently, these dimension parameters do not equally influence the performance of stone columns in lessening soil deformation. Hence, comparative analysis was carried out in the current study to find out the dimension parameter to which deformation of stone column reinforced weak ground is most sensitive. Finite element based parametric numerical analysis was conducted to simulate the weak ground reinforced with a group of granular piles supporting light weight building. For the parametric study, five dimensions for each parameter (diameter, spacing and length) were considered. The dimensions were purposely varied by uniform percentage increase. Field settlement monitoring data was used to track deformation response of the site and validate the finite element results. The numerical analysis reveals that the simulation results have good agreement with the field settlement monitoring data. From sensitivity view point, column spacing was found to be the most controlling and influential parameter affecting deformation of the reinforced weak soil. Similarly, column length is the dimension parameter to which ground deformation is least sensitive.

Copyright of Revista Foco (Interdisciplinary Studies Journal) is the property of Revista Foco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

An industrial by-product known as fly ash is produced when coal is burned for electricity production and is considered an environmental pollutant. A comprehensive fly ash utilisation programme must be implemented to reduce environmental pollution, including numerous factors at different levels. Fly ash's geotechnical qualities, including its specific gravity, permeability, internal angular friction, and consolidation characteristics, make it ideal for structural fill, particularly on clay soils, when building highways and embankments. Much research has been conducted on how fly ash affects soil stability. In order to determine the impact of fly ash addition on soil properties, this inquiry reviewed a few of these papers and conducted a critical assessment. This study also looked at combining fly ash and clay soil. Numerous investigations indicate that fly ash generally improves soil stability, notably when analysing CBR values and soil permeability, and reduces volumetric changes in the soil. The ground becomes compact due to particle size and form and a decrease in volumetric dilatation. Because the additives to the hardened soil do not dissolve, the soil's behaviour continues to be modified. [ABSTRACT FROM AUTHOR]

Copyright of Karaelmas Science & Engineering Journal / Karaelmas Fen ve Mühendislik Dergisi is the property of Karaelmas Science & Engineering Journal and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The effects of soil texture on trace metal concentrations and geochemical fractions in an apple orchard soils were investigated. For this purpose, soil samples were taken from the apple orchards with two different soil textures located on the same geomorphological unit in Çanakkale, Turkey. A wet digestion was used to determine total trace metal concentrations, and a sequential extraction method was used to determine geochemical fractions of the metals. According to average total concentrations of all metals, except Pb, were found to be significantly higher (p < 0.05) in clay soils. Sequential extraction analysis showed that potential mobile fractions were ordered as Cd (68.8%) > Pb (52.4%) > Cu (42.0%) > Zn (34.8%) > Ni (32.3%) > Cr (22.9%) in clay soils and as Cd (61.6%) > Pb (51.6%) > Cu (40.2%) > Zn (30.7%) > Ni (30.8%) > Cr (24.9%) in loamy soils. The results revealed that all metals, except Pb, in exchangeable/acid soluble, oxidizable and, potential mobile fractions were found to be significantly higher in clay soils (p < 0.05). It was figured out that clay contents played an effective role in total concentrations of metals and their distribution in geochemical fractions. [ABSTRACT FROM AUTHOR]

In addition to creating environmental threats, the leakage and entrance of chemical fertilizers into soil, which is possible in various ways, dramatically changes the physical and mechanical properties of soil. Furthermore, clay soils in the vicinity of monoammonium phosphate (MAP) contamination show substantially negative behavior, thus, improving the engineering geological factors of soil has become a huge challenge for engineers. Extensive programs such as triaxial compression test, consolidation test, compaction test, Atterberg limits, and collapse tests, in addition to X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX) were performed on samples containing 10%–30% MAP over 7 days, 1, and 3 months. The mentioned trend was repeated when 0.5%–3% nano A (Al2O3 in alpha phase), nano F (Fe2O3 in alpha phase), and AF in form of a nanohybrid were added to soil which had been contaminated by MAP. Gained reports demonstrated significant declines in maximum dry density, plasticity index, and shear strength of contaminated soil when compared with natural soil. Conversely, increases in liquid limit, plastic limit, consolidation settlement, as well as soil collapse index were observed. Furthermore, a decrease in the amount of minerals in the XRD results and the formation of a flocculated structure in the SEM images in MAP-contaminated soil are evident. According to microstructural analysis, adding nano A, nano F, and AF nanohybrid as an improvement phase caused remediation of the soil structure and created cementation bonds between soil particles, thereby increasing the maximum dry density and soil shear strength, and decreasing the consolidation settlement and soil collapse index. Therefore, the use of AF as an efficient additive to remediate physical and mechanical properties of soils that have been contaminated with MAP, and to decrease the geological hazards of these kinds of contamination is recommended. [ABSTRACT FROM AUTHOR]

Grassland production based on cutting-only and an increasing frequency of prolonged periods of drought due to climate change could lead to decreased productivity in Lolium perenne. In field experiments, we tested whether Festuca arundinacea and Phleum pratense could be suitable alternatives to L. perenne on intensively managed grassland on clay, peat and sandy soil. The three grasses were sown in mixture with Poa pratensis and Trifolium repens and subjected to different frequencies of defoliation representing a cutting-only system, simulated grazing system and a mixed system. We found that in systems with at least six defoliations, F. arundinacea represented an acceptable compromise between feed quality (6.4 MJ net energy/kg dry matter (DM), 19.3% crude protein, CP), persistence (mass proportion >90%), and DM yield (12.7 Mg/ha). However, for dairy production based on intensive cutting-only systems, the quality of F. arundinacea was insufficient (5.9 MJ net energy/kg DM, 15.6% CP). Mixtures with P. pratense as the main sown species did not differ significantly in production of net energy and CP from L. perenne in cutting-only systems on sandy soil. On peat land, all sown mixtures were invaded by Holcus lanatus. We found that under frequent defoliation conditions, H. lanatus -rich swards had comparatively good DM yields (9.2 Mg/ha) and a feed quality that would be sufficient for dairy cow nutrition (net energy, 6.2–6.4 MJ/kg DM; 18.8–20.4% CP). We conclude that there is potential to adapt the choice of grasses and mixtures in different production systems to meet the challenges of climate change. [ABSTRACT FROM AUTHOR]

Soft to medium clay soil possesses major sources of damages to the pavement layers overlying them because of their potential failure under moisture changes and external heavy traffic load. In such situations, soil stabilization methods can be used to improve the soil properties and satisfy the desired engineering requirements. This study presents the use of sugarcane bagasse ash (SBA) and lime as chemical stabilizers for a clay soil subbase. Sugarcane bagasse ash and lime are used individually and as mixtures at varying percentages to stabilize a clay soil from Taxila, Pakistan. Various geotechnical laboratory tests such as Atterberg limits, compaction test, and California Bearing Ratio (CBR) are carried out on both pure and stabilized soils. These tests are performed at 2.5%, 5%, and 7.5% of either SBA or lime by weight of dry soil. In addition, mixtures of lime and SBA in ratios of 1:1, 2:1, 3:1, 1:2, and 1:3 are used in 5%, 7.5%, and 10% of dry soil weight, respectively. Results indicate that soil improved with 7.5% SBA showed a 28% increase in the liquid limit, while soil mixed with 2.5% lime in combination with 7.5% SBA showed an increase of 40% in the plastic limit. For the plasticity index, the soil mixed with 7.5% SBA showed an increase of 42%. Moreover, 2.5% lime in combination with 2.5% SBA showed the best improvement in soil consistency as this mixture reduced the soil plasticity from high to low according to the plasticity chart. Furthermore, 2.5% SBA in combination with 5% lime demonstrated the largest improvement on the CBR value, which is about a 69% increase above that of the pure soil. Finally, the cost analysis indicates a promising improvement method that reduces pavement cost, increases design life, and mitigates issues of energy consumption and pollution related to SBA as a solid waste material.

Construction of earth fill dams offers a cost-effective solution for various purposes. However, their susceptibility to internal soil erosion, known as piping, poses a significant risk of structural failure and resultant loss of life and property. Soil stabilization emerges as a practical technique to fortify these dams against such threats. This study investigated the impact of lime on the internal erosion properties of clay soils, focusing on CH and ML soil types. Specimens of different lime content were prepared and remolded at 95% relative compaction and optimum moisture content. Hole Erosion tests at varying lime concentrations and curing durations were adapted to conduct the investigation. This investigation aims to optimize lime content and curing time for cohesive soil stabilization against internal erosion. Findings revealed that 2% and 5% of quicklime, by dry weight of the soil, effectively stabilized CH and ML soils, respectively, against internal erosion, with a two-day curing period proving optimal. Furthermore, the addition of lime significantly enhanced erosion rate index and critical shear strength in clay soil, underscoring its efficacy in soil stabilization efforts.

This paper investigates the viability of stabilizing expansive brown clays in the Northern region of Jordan using a local bituminous oil shale ash from El-Lajjun, Jordan. A comprehensive experimental programme was designed to i. examine the impact of oil shale ash dose by weight on the strength gain. ii. Evaluate oil shale ash stabilized clays' consolidation and volume change behaviour during loading and unloading. Results revealed that adding 20 % bituminous OSA remarkably improved expansive brown clays' engineering properties and mechanical behaviour. An increase of 140 % in the unconfined compressive strength and a reduction of 19.3 % in the permeability coefficient was obtained at 20 % OSA. Also, the Unconfined Compressive Strength tests revealed that the strength of OSA-treated expansive clays is significantly affected by the curing time. Increases of 35.1 % and 65.7 % in the unconfined compressive strength were achieved after 7 days and 21 days of curing, respectively. Furthermore, the addition of OSA showed an effect on compressibility behaviour, reducing settlement. Regarding the consolidation parameters, the inclusion of 20 % OSA reduced the compression index (Cc) and swelling index (Cs) by 42.67 % and 72.6 %, respectively.

Soil stabilizer can improve the physical and chemical properties of clay and improve the bearing capacity of subgrade soil. A kind of liquid polymer soil stabilizer of vinyl acetate-ethylene was used in this paper. First of all, the effects of stabilizer content and curing time on the unconfined compressive strength (UCS) and the water stability were studied to clarify the strength evolution of stabilized soil. Furthermore, the pH test, Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDS), X-Ray Diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FTIR) were performed to study mineralogy, morphology, and chemistry of clay minerals and polymer stabilizer, as well as the potential interaction of the both. The results show that the stabilized soil has a quick strength growth before 14d that reaches about 89% of the final strength, then followed by a decreasing growth rate. Extending the curing time and increasing stabilizer content contribute to the dense agglomeration structure and homogenous skeleton structure. When immersed in the water, the strength has the largest reduction amplitude within the first day. The pore-filling effect, physicochemical bonds, and surface wrapping for clay particles are dominating roles of the polymer stabilizer. The formed fine colloidal particles could fill micro-pores distributed in the matrix. In addition, the polar functional group of carbonyl could create a strong electrostatic attraction and hydrogen bond with the clay minerals, further improving the adhesion, while there are no other new function groups generated. The polymers containing hydrophobic groups are recommended in consideration of water stability.

The object of the study is frame-gantry pile foundations embedded in the soil base. To improve the strength of weak soil base, various methods of reinforcement are used, including the foundation constructions in the form of wedge-shaped piles. The paper deals with laboratory studies of the soil base during the installation of small-scale wedge-shaped piles at different angle. The process of soil shearing under the influence of the loads is registered by deformation control benchmarks arranged in the form of a square grid. The interaction between the soil and the frame-gantry foundations appears in a change of the physical and mechanical characteristics in the near pile area. The tests revealed that when piles are installed at the angle of 30° the bearing capacity of the foundation increased. The average density in the fixed active zone of the soil area increased by 12 %, and the average porosity coefficient decreased by 20 %. The deformation modulus changed by 1.8–2.3 times. The angle of internal friction remained virtually unchanged.

Environmental-friendly sodium hydroxide and sodium silicate congenial with ordinary Portland cement (OPC) are used as soil stabilizing agents in this study. This research involves experimenting with the use of cement admixed with sodium silicate (SS) and sodium hydroxide (SH) to enhance the strength of clay soil. The type of admixtures, the proportion of admixtures, the binder material, and the curing time were the experimental variables in this study. An unconfined compression test was used to determine the compressive strength of stabilized clay soil with various admixtures. Based on the experimental results, the maximum value of UCS of clay soil was estimated to be 215.22 kPa for the optimum dosage of admixtures (10% OPC + 4% SS + 8 molarity of SH). Besides, the maximum young's modulus of soil was achieved as 8.353 MPa. The effect of pH on the different admixtures of soil samples was evaluated and discussed in this study. Scanning electron microscope (SEM) studies confirm the formation of hydration and pozzolanic constituents and show that after being treated with OPC, SH, and SS, resulted in clay soil appears to form denser microstructures. [ABSTRACT FROM AUTHOR]