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The compression index of fine-grained soils is a critical parameter for determining structure settlement. In the laboratory, determining this parameter is time-consuming, costly, and laborious. Alternatively, determining this significant parameter based on soil index properties can be advantageous for preliminary design. This work compiled more than 1500 datasets to review and assess the valid correlation and, secondly, incorporate the index properties to better estimate the compression index of the fine-grained soils. This work indicated that previously established correlations, from which an individual index property provides the compression index values, cannot be applicable for many datasets and different types of fine-grained soil. Multivariable regressions were utilized to represent the actual properties of the soil and estimate the compression index. Concerning the analysis, models that incorporate the liquid limit, plasticity index, and initial void ratio can be utilized as good models. Different advanced mathematical models were employed to improve the accuracy of the model, including multivariable non-linear regression (MNLR), full quadratic (FQ), and full quadratic with high-order interaction (FQHOI). The result indicated that FQHOI can perform better than the other models. Finally, sensitivity analyses were conducted to highlight a parameter with the most influence on the compression index, and the results indicated that the initial void ratio had a superb influence on the value of the compression index. [ABSTRACT FROM AUTHOR]

Sandstone is a key material in many global heritage sites, including Jaisalmer Fort (Rajasthan), Petra (Jordan), and Angkor Wat (Cambodia). Its versatility makes it a popular building material, but environmental factors such as climatic conditions and fire incidents can cause significant damage. These factors can induce formation of microscopic changes, fissures, fractures, and intergranular porosity, leading to early failure. This vulnerability is of especial concern for heritage structures, where preserving the cultural and historical assets is critical task. In recent years, the frequency of fire incidents affecting heritage structures has increased such as the National Museum of Brazil fire in 2018, and the Notre Dame fire in 2019. Accurate assessment is crucial for developing effective remediation protocols for fire-damaged structures and ensuring the longevity of sandstone heritage sites globally. This study investigates the physical and mechanical properties of thermally treated Jodhpur sandstone, focusing on the role of cooling. The results demonstrate that various cooling methods, such as furnace cooling, air cooling, and water cooling, significantly influence the properties of sandstone. Specifically, the water-cooled specimens experienced the highest level of damage, characterized by the greatest decreases in density, uniaxial compressive strength (UCS), elastic modulus, and wave velocities. These findings underscore the importance of controlled cooling in heritage conservation, providing a scientific basis for improving preservation strategies for sandstone monuments exposed to thermal stress. [ABSTRACT FROM AUTHOR]

Projects related to Geotechnical Engineering require thorough ground study to know the soil behaviour thus making it necessary to determine the strength and stability parameters of soil. The soils of Assam are primarily of four types viz., Alluvial (old and new), Piedmont, Hill and Lateritic soils with the alluvium abundantly available in the state. The most important soil parameters are the shear strength parameters, namely, cohesion (c) and angle of internal friction (Φ) which can be obtained using triaxial tests with different drainage conditions. But one triaxial test may take weeks to complete and are very expensive. Moreover, for large projects it is practically preposterous to conduct large number of triaxial tests. Hence, an alternate way is to develop a relation between different parameters which enable us to determine others. The main objective of this study is establishing prediction models that allow the shear parameters to be predicted from soil index properties. For this, three prediction models are developed by combining various soil parameters viz., Liquid Limit (LL), Plastic Limit (PL), Specific Gravity (G) and Optimum Moisture Content (OMC) using Multivariate Regression Analysis (MRA) and Artificial Neural Network (ANN). The results show better performance for ANN than MRA. [ABSTRACT FROM AUTHOR]

Abstract This study presents the findings of a comprehensive geotechnical and seismic site investigation conducted at Otuasega Town located in Bayelsa State within the Niger Delta region of Nigeria. Subsurface exploration involved advancing 10 boreholes to 30 m depth using hollow stem auger drilling. Continuous disturbed and undisturbed soil sampling was performed at 1.5 m intervals for detailed geotechnical testing. Laboratory tests on the recovered soil samples established the index properties, classification, densities and consistency limits of the stratified deposits. The subsurface profile comprised alternating layers of clay, silt and sand typical of deltaic sediments, with the clay fractions exhibiting medium to high plasticity. Shear wave velocity (Vs) profiling using Multichannel Analysis of Surface Waves (WASW) techniques categorised the site predominantly as Site Class C and D based on international standards. The Standard Penetration Test (SPT) N-values ranged from 5 to 10, indicating soft normally consolidated clay conditions typical of the Niger Delta region. Predictive empirical models developed from the field and lab data showed strong correlations for estimating key geotechnical parameters such as SPT blow count, Vs and liquefaction resistance. Ground response analyses using the Vs and SPT data indicated significant site amplification potential, with peak ground accelerations up to 1.5 times the bedrock motion. Liquefaction analysis based on the empirical SPT-based methods revealed a high potential for liquefaction in the sandy layers, especially under strong earthquake shaking. The study characterized the complex sedimentology and provided baseline information for seismic microzonation and site-specific ground response analyses to advance understanding of geohazards in this delta environment.

This study presents the findings of a comprehensive geotechnical and seismic site investigation conducted at Otuasega Town located in Bayelsa State within the Niger Delta region of Nigeria. Subsurface exploration involved advancing 10 boreholes to 30 m depth using hollow stem auger drilling. Continuous disturbed and undisturbed soil sampling was performed at 1.5 m intervals for detailed geotechnical testing. Laboratory tests on the recovered soil samples established the index properties, classification, densities and consistency limits of the stratified deposits. The subsurface profile comprised alternating layers of clay, silt and sand typical of deltaic sediments, with the clay fractions exhibiting medium to high plasticity. Shear wave velocity (Vs) profiling using Multichannel Analysis of Surface Waves (WASW) techniques categorised the site predominantly as Site Class C and D based on international standards. The Standard Penetration Test (SPT) N-values ranged from 5 to 10, indicating soft normally consolidated clay conditions typical of the Niger Delta region. Predictive empirical models developed from the field and lab data showed strong correlations for estimating key geotechnical parameters such as SPT blow count, Vs and liquefaction resistance. Ground response analyses using the Vs and SPT data indicated significant site amplification potential, with peak ground accelerations up to 1.5 times the bedrock motion. Liquefaction analysis based on the empirical SPT-based methods revealed a high potential for liquefaction in the sandy layers, especially under strong earthquake shaking. The study characterized the complex sedimentology and provided baseline information for seismic microzonation and site-specific ground response analyses to advance understanding of geohazards in this delta environment. [ABSTRACT FROM AUTHOR]

This study carried out comparative analyses of the potentials of induction furnace slag (IFS), rice husk ash (RHA) and saw dust Ash (SDA) on the geotechnical properties of the A-7-6 and CL classified laterite soil obtained from Imota, Lagos State. By these classifications, the laterite soil is a poor subgrade material that requires stabilization before it could be utilized for engineering applications. Moreover, IFS, RHA and SDA are agro-industrial waste materials, whose poor disposal systems pose serious concerns to the environment. As one of the sustainable ways of reusing these wastes, the laterite soil was treated with 0-10% of these wastes by mass of the soil sample. The impacts of these admixtures on the grain size distribution, specific gravity, Atterberg limits, compaction, uniaxial compressive strength (UCS) and California bearing ratio (CBR) were determined based on relevant standard procedures. The study revealed that the percentage of specimen passing 0.075 mm sieve increased with increase in admixture contents. However, the specific gravity of the soil decreased with the addition of RHA and SDA but increased significantly with IFS treatment. The plasticity index of the stabilized samples reduced with increasing IFS content, while it increased with RHA and SDA additions. UCS values increased from 108.90 kPa for the natural soil to 150.90 kPa, 146.57kPa and 121.52 kPa at 10% addition of IFS, RHA, and at 8% SDA, respectively. The CBR increased from 63.38% for the natural soil to 157.19%, 98.98% and 88.94%, and from 9.12% to 38.59%, 24.74% and 14.13%, for IFS, RHA, and SDA, respectively under unsoaked and soaked conditions, respectively at 10% stabilization. The research findings indicate that IFS have significant impacts on soil properties than RHA and SDA, and the addition of 4% IFS makes this soil a suitable material for both subgrade and sub-base road courses. [ABSTRACT FROM AUTHOR]

The soil–water characteristic curve (SWCC) is an important parameter of unsaturated soil, and almost all the engineering characteristics of unsaturated soil are more or less related to the SWCC. The SWCC contains important information for geotechnical engineering, water engineering, hydrogeology modelling and climate modelling. It is noted that the experimental measurement of SWCC is costly and time consuming, which limits the implementation of principles of unsaturated soil mechanics in practical engineering. The indirect method, which estimates the SWCC from the index properties of soil, can provide the SWCC with the errors which are within tolerance in practical engineering. In addition, the indirect method can determine SWCC very fast and almost with no cost. In this paper, the domestic sandy soils are selected and the index properties of those sands are used to correlate the SWCC fitting parameters. Consequently, mathematical equations are proposed to estimate SWCC from index properties of domestic sands. The proposed models are trained from 44 sets of experimental data and verified with another independent 8 sets of experimental data from published literature. It is observed that the results from the proposed model agree well with the experimental data from literature. [ABSTRACT FROM AUTHOR]

Expansive soil dual behavior (swell/shrink) exhibits high compressibility and volumetric instability against the frequent moisture imbalance, rendering premature failure of lightweight structures. The present research highlighted the geotechnical behavior of expansive soil treated with industrial waste pozzolanic fly ash (FA) materials. Fly ash, a leftover from coal burning in power plants is considered a problematic solid waste globally. The typical disposal technique for fly ash can lead to the degradation of flora and fauna and contamination of fertile land. However, numerous research studies reveal that fly ash can be used to effectively strengthen the geoengineering properties, including physical, chemical, and biological. This paper critically reviews past research on the efficiency of fly ash as a soil stabilizer in enhancing the mechanical behavior of expansive soils. The effect of varying dosages and types of fly ash in soil mixture on the Atterberg limits, unconfined compressive strength (UCS), California Bearing Ratio (CBR), and swell potential is critically reviewed through a series of geotechnical and microstructural characterization tests. The addition of varying percentages of fly ash (25–40%) to expansive soil shows an improvement in plastic behavior (up to 30–33%), compressive shear strength (40–48%), penetration resistance (52–55%) with least swelling (42–48%), and compressibility (36–40%) of fly ash-soil. Furthermore, the volumetric stability (swell/shrink) of clayey soil is attributed to mineral alteration and chemical compositions due to active pozzolanic reactions. This study may prove to be very effective in devising an alternative stabilizer to address the dual nature problems associated with expansive soil.

This study evaluated the index and physico-chemical characteristics of lateritic soil classified as A-2-6 (1) in the American Association of State Highway and Transportation Officials (AASHTO) system and SC in the Unified Soil Classification System (USCS) treated with stepped Bacillus sphaericus (Bs) suspension densities (i.e., 0, 1.5 × 108, 6.0 × 108, 1.2 × 109, 1.8 × 109, 2.4 × 109 cells/mL) for varying cementation reagent (Cr) concentrations (i.e., 0.25, 0.5, 0.75 and 1.0 M), using 25 Bs:75 Cr, 50 Bs:50 Cr, and 75 Bs:25 Cr mix ratios, respectively. The results obtained show that the optimum calcium carbonate contents were 9.0%, 8.7%, and 6.5% for the mix ratios stated above, respectively, for Bs (1.2 × 109 cells/mL) and Cr (0.5 M) with urease activity of 80.8 ms/cm and an optimum pH of 8.99. The bio-treatment of soil with 25% bacteria (1.2 × 109 cells/mL) and 75% Cr (0.5 M) mix ratio reduced the liquid limit (LL) of the natural soil from 36.5 to 34.2%, and the plasticity index (PI) from 16.4 to 11.6%. A microanalysis of specimens showed that the treated soil appeared more uniform and aggregated. The findings of the study show that bio-treatment with 25 Bs (1.2 × 109 cells/mL):75 Cr (0.5 M) mix ratio improved the index and physico-chemical properties of the lateritic soil considered in the study. [ABSTRACT FROM AUTHOR]

Electrical resistivity measurement is a quick and non-destructive method to characterize various materials in different applications. Compared to field and laboratory tests, predicting the soil properties from resistivity monitoring becomes an attractive alternative for engineering practice. The electrical resistivity of soil is sensitive to the physical–chemical soil properties, chemical activity of the pore fluid, weather and environmental conditions, and test frequency Thus, the main challenge consists in defining a reliable methodology and models to deal with so many variables. The objectives of the current study were to collect data from different geological formations and to correlate the electrical resistivity to the soil properties. In this study, over 400 data from several research studies were used to characterize the relevance of the various parameters. A new hyperbolic model was developed and compared with the power and exponential expressions to define the best-fitting model. The coarse fraction, the type and percentage of clay minerals, and the water content are the main parameters that control soil resistivity. The relationships between soil resistivity and degree of saturation, which incorporates both the soil structure and water content, revealed the best curve fitting and yet with no dependence on the compaction energy. The influence of temperature is suppressed by normalizing the electrical resistivity to the corresponding value at a standard temperature. Vipulanandan hyperbolic correlation provided better curve fittings with coefficients of determination ( R 2 ) above 0.9. [ABSTRACT FROM AUTHOR]

This paper describes the geotechnical characteristics of index and deformation properties of Stockholm clays. These clays exhibit large variations both geographically and with depth. The clays range from highly organic clays with high plasticity to silty clays with low plasticity. First, the geological conditions of the clays are outlined to qualitatively explain the typical soil stratigraphy encountered in the Stockholm area. Second, two large generic databases are presented, containing 3,500 and 1,600 data points, respectively. The data originates from routine testing and constant rate of strain oedometer tests conducted in commercial projects. The data is analyzed and compared with results from high quality block sampling. It is seen that a common feature of the clays are low undrained shear strengths, and consequently low yield stresses and oedometer moduli. Further, several deformation properties such as preconsolidation pressure and several oedometer moduli is shown to depend on the soils natural water content and its plasticity. Differences in sample quality is shown to highly affect some properties, highlighting the importance of quality sampling and handling of samples. Criteria for sample quality for this type of clay is proposed based on the oedometer moduli before and after the preconsolidation pressure. The paper can hopefully work as a useful reference to engineers working on similar soils worldwide.

The massive annual tonnage of iron ore tailings, plus the more demanding environmental policies after the catastrophic collapses of Fundão Dam in 2015 and Feijão Dam I in 2019, have forced Brazilian mining companies to search for more sustainable and safer alternatives for tailings disposal. The Brazilian mining industry has been studying the dry stacking of filtered tailings. Most companies seek the development of great dry stacks, over 200 m high, to absorb the whole tailings generation. As tailings assume a structural role, it is vital to characterize the dry stacks and understand their behaviour. This study aimed to characterize index properties, evaluate the effect of compaction on the hydraulic behaviour, and evaluate field variability of iron ore tailings from a mine in Quadrilátero Ferrífero, Brazil. Also, a database of iron ore tailings properties from Quadrilátero Ferrífero was collected and used to evaluate the results. Specimens were compacted to 93%, 95%, 97%, and 100% of Proctor's maximum dry unit weight, and the hydraulic conductivity was defined for several confining pressures (100, 200, 400, 800, 1600 and 1900 kPa) for each degree of compaction. Index properties of the studied tailing were similar to other iron ore tailings from the Quadrilátero Ferrífero, hydraulic conductivity was proportional to the void ratio, and the field tests indicated some variability of both material properties and degree of compaction of the stacked material. The database presented in this study supplies the mining industry with a reference point for future projects. [ABSTRACT FROM AUTHOR]

One of the reasons that cause premature deterioration of the wearing course is the quality of the materials that make up the flexible pavement structure of the road network in Ecuador. Therefore, there is a need to thoroughly study the stone materials, such as coarse aggregate and fine aggregate, which form the structure of the flexible pavement. The quality of these materials will determine the service life of the wearing course as well as the high or low cost of road construction. The main objective of this research was to determine the highest quality material based on its technical and economic characteristics. For this purpose, three main mines that supply stone materials in the country were selected: "Kumochi", "Los Muelles", and "Cantera El Salvador". Several samples of fine aggregate and coarse aggregate were taken from these mines to conduct laboratory tests, including natural moisture content, Atterberg limits, gradation, modified Proctor, and relative density. The California Bearing Ratio (CBR) test was also performed to determine the load-bearing capacity of the samples. These data will be used in future investigations for the design of sustainable pavement structures. Additionally, physical and mechanical properties were determined through tests including aggregate soundness, resistance to abrasion, and the Los Angeles abrasion test to determine the percentage of fractured faces of the coarse aggregate. In conclusion, it was found that the material from the "El Salvador" mine has the best technical and economic characteristics for the formation of flexible pavement structures. However, the material from the "Kumochi" and "Los Muelles" mines met the standards of the international AASHTO norm. The final recommendation after conducting the research is that the aforementioned materials can be used not only for the formation of the pavement structure but also for the wearing course. [ABSTRACT FROM AUTHOR]

California Bearing Ratio (CBR) of the subgrade soil is one of the essential values for the design and construction of the asphalt pavement of highway projects. However, the estimation of the CBR value through laboratory tests is time-consuming and labor-intensive. Thus, this study focuses on providing artificial neural network (ANN) prediction models that can be efficiently used for the prediction of the CBR value of the subgrade soil in Egypt from the grain size distribution, Atterberg limits, and compaction parameters. 240 ANNs with different hyperparameters are investigated in order to optimize the hyperparameters so that the final chosen ANN can provide accurate results. The analysis shows that the deep neural networks outperform the shallow ANNs. Finally, comparing the performance of the ANNs with the traditional multiple linear regression (MLR) shows that ANNs outperform the MLR models as the ANNs have much better performance and can generate highly accurate predictions.

This paper describes an in-depth soil characterization study in the La Carolina financial district of Quito (Ecuador). As there was very little information available on the geotechnical structure of Quito's volcanic soil, particularly in this area, where large-scale property development has taken place, the aim was to provide information on soil parameters to engineers working on large geotechnical and civil engineering projects based on the results of a thorough and comprehensive study of such properties. A series of field tests were performed at three different sites, where thin-walled tube samples were collected for lab testing to estimate the index properties and mechanical parameters. These index properties were then combined with conventional two-way drainage oedometer tests and stress-path triaxial testing to evaluate compressibility, stiffness and strength. The subsoil was found to be partly composed of slightly overconsolidated volcanic soils. X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) analyses were also conducted to determine mineralogical and microstructural features and evaluate their influence on the mechanical behavior of the volcanic soil. This type of research is frequently applied to the study of landslides in urban environments, where it is essential to understand their failure mechanisms, especially in slopes generated by the construction of important engineering works. Therefore, based on this geotechnical characterization study, parameters were subsequently determined for the Mohr–Coulomb (MC), Hardening Soil (HS), and Hardening Soil with Small-Strain Stiffness (HSsmall) soil constitutive models, and these were applied to a numerical study of the Soil Nailing system behavior for the construction of a five-level underground car parking structure of an important building located in the north-central sector of the city of Quito. It was verified that the HSsmall and HS constitutive soil models better reproduce the behavior of this type of structure. Finally, the multiple geotechnical parameters determined in this study significantly contribute to the analysis of these structures in this soil type. [ABSTRACT FROM AUTHOR]

The current research focuses on nanoparticles' ground-improvement potential using clayey soil mixed with varying amounts of the nanoparticles "Silicon Carbide". With an increase in the amount of nanomaterial, a tendency of improvement has been recorded in liquid and plastic limits, as well as the plasticity index. The maximum reduction in liquid limit (15.8%), plastic limit (13.6%), and plastic index (18.7%) was recorded at 0.25 gm of Silicon Carbide as compared to control (0 gm of SiC). There was a 26.7% and 33.3% increase in the cohesion of soil at 0.25 gm and 0.3 gm of Silicon Carbide, respectively. Furthermore, when the Silicon Carbide content increased from 0.25 gm, the rate of increment of friction angle also increased. It was 87.5% and 137.5% at 0.25 gm and 0.3 gm of Silicon Carbide, respectively. Furthermore, 0.3 gm of Silicon Carbide, is found to be optimal within the scope of the experiment as at this amount of Silicon Carbide both cohesion and angle of friction attained maximum. XRD, SEM, and FTIR were used to confirm the findings. It concludes that by using even a small amount of nanomaterial, an appreciable change in the properties of clayey soil can be obtained in the field. [ABSTRACT FROM AUTHOR]

This paper describes the geotechnical characteristics of index and deformation properties of Stockholm clays. These clays exhibit large variations both geographically and with depth. The clays range from highly organic clays with high plasticity to silty clays with low plasticity. First, the geological conditions of the clays are outlined to qualitatively explain the typical soil stratigraphy encountered in the Stockholm area. Second, two large generic databases are presented, containing 3,500 and 1,600 data points, respectively. The data originates from routine testing and constant rate of strain oedometer tests conducted in commercial projects. The data is analyzed and compared with results from high quality block sampling. It is seen that a common feature of the clays are low undrained shear strengths, and consequently low yield stresses and oedometer moduli. Further, several deformation properties such as preconsolidation pressure and several oedometer moduli is shown to depend on the soils natural water content and its plasticity. Differences in sample quality is shown to highly affect some properties, highlighting the importance of quality sampling and handling of samples. Criteria for sample quality for this type of clay is proposed based on the oedometer moduli before and after the preconsolidation pressure. The paper can hopefully work as a useful reference to engineers working on similar soils worldwide. [ABSTRACT FROM AUTHOR]

The properties of residual soils, according to literature, are sensitive to the pre-test drying method given to the sample prior to testing. Similarly, residual soils such as laterites/lateritic soils are formed under various climatic conditions; hence, they show different degrees of sensitivity to the pretest drying method. This work is therefore carried out to elucidate the influence of the pre-test drying temperature or method on the properties of three lateritic soils that developed over three different Pre-Cambrian basement complex rocks from Ado-Ekiti, SW, Nigeria. The soils were subjected to two pre-test drying temperatures before conducting laboratory tests. The pre-test drying temperatures considered in this study include air-drying, oven-drying at 60 °C, and oven-drying at 110 °C. Pre-test drying at 60° and 110 °C caused particle aggregation (which reduced the soil surface area) and loss of cohesion. Consequently, this reduced the specific gravity, optimum moisture content, clay content, consistency limits, and unconfined compressive strength of the lateritic soils. The maximum dry density and sand content increased as the pre-test drying temperature increased. The pre-test drying temperature did not significantly change the plasticity classification of the soils; however, at higher pre-test temperatures, the soils become less plastic. The free swell index of the lateritic soils increased with increasing pre-test drying temperatures (up to 60 °C) before decreasing when the temperature rose to 110 °C. This study has revealed the effect that pre-test drying temperatures may have on the properties of lateritic soils, and these may produce soil properties that do not likely indicate the actual field performance of the tested soils. [ABSTRACT FROM AUTHOR]

Sedimentary Rocks composing the Thar Lignite basin Pakistan are of clastic origin. These rocks have comparatively low uniaxial compressive strength (UCS) values, and hence recognized as ‘soft sedimentary rocks’ in this study. UCS is a fundamental property of rocks, used by mine design engineers in designing the surface and underground excavations. The purpose of this study is to investigate the relationship between UCS with Brazilian tensile strength (BTS), and index properties of soft sedimentary rock formations at Thar Lignite basin. Various correlations between mechanical and physical properties of rocks have been developed previously. However, no significant correlation has been developed on UCS with BTS and index properties for soft sedimentary rocks. Numerous Rock samples from Two complete geotechnical drillholes at Block-IX Thar Coalfield were selected. Standard test procedures were implemented to determine the UCS, indirect Tensile and index properties such as point load strength, and shore Scleroscope hardness. The correlations between rock properties were established using simple and multiple regression techniques, and empirical equations were obtained. These equations can be used to predict the UCS and tensile strength of soft sedimentary rocks by performing simple index tests; which are quick, economical, and easier to be performed on the site. [ABSTRACT FROM AUTHOR]

The aim of this investigation is to determine the effect of drying temperature on the geotechnical properties of natural soils and stabilised soils. Soil samples were taken along Supare Akoko- Emure Ekiti road from three locations at the depth of 1m each. Soil sample for location 1 soil was taken from a stable section while soil samples from locations 2 & 3 were taken from the failed portions of the road. The following laboratory analysis were conducted on the soil samples; atterberg limit test, grain size analysis, Linear shrinkage, Specific gravity, Compaction test and California Bearing Ratio test (CBR). The results show that sampled soil from location 1 has better engineering properties than soil samples from Loc. 2 and 3. This is an indication that the soils of locations 2 & 3 contributed to the failing of the failed part. These three soil samples were further tested by adding 6% (of the total weight of the sampled soils) of Saw dust ash (SDA) and Fine Palm kernel shells (FPKSA) to the soil as stabilisers. Both the index and strength properties improved upon the addition of stabilizers with SDA proving to be a better stabiliser. Under varying temperature of pretest drying with stabilisers (SDA and FKPSA) and without stabiliser; the same engineering properties were considered. The results show that temperature plays a major role to better the properties of the soil.

The properties of residual soils, according to literature, are sensitive to the pre-test drying method given to the sample prior to testing. Similarly, residual soils such as laterites/lateritic soils are formed under various climatic conditions, hence they show different degrees of sensitivity to pretest drying method. This work is therefore carried out to elucidate the influence of pre-test drying temperature or method on the properties of three lateritic soils that developed over three different Pre-Cambrian basement complex rocks from Ado-Ekiti, SW, Nigeria. The soils were subjected to three pre-test drying temperature before conducting laboratory tests. The pre-test drying temperature considered in this study include air-drying, oven-drying at 60° C, and oven-drying at 110° C. Pre-test drying at 60° and 110° C caused particle aggregation (which reduced the soil surface are) and loss of cohesion. Consequently, this reduced the specific gravity, optimum moisture content, clay content, consistency limits, and unconfined compressive strength of the lateritic soils. The maximum dry density and sand content increased as the pre-test drying temperature increases. The pre-test drying temperature did not significantly change the plasticity classification of the soils, however, at higher pre-test temperature the soils become less plastic. The free swell index of the lateritic soils increased with increasing pre-test drying temperature (up to 60° C) before decreasing when the temperature rose to 110° C. This study has revealed the effect pre-test drying temperature may have on the properties of lateritic soils and these may produce soil properties that may not likely indicate the actual field performance of the tested soils.

This study evaluated the index and physico-chemical characteristics of lateritic soil classified as A-2-6 (1) in the American Association of State Highway and Transportation Officials (AASHTO) system and SC in the Unified Soil Classification System (USCS) treated with stepped Bacillus sphaericus (Bs) suspension densities (i.e., 0, 1.5 × 108, 6.0 × 108, 1.2 × 109, 1.8 × 109, 2.4 × 109 cells/mL) for varying cementation reagent (Cr) concentrations (i.e., 0.25, 0.5, 0.75 and 1.0 M), using 25 Bs:75 Cr, 50 Bs:50 Cr, and 75 Bs:25 Cr mix ratios, respectively. The results obtained show that the optimum calcium carbonate contents were 9.0%, 8.7%, and 6.5% for the mix ratios stated above, respectively, for Bs (1.2 × 109 cells/mL) and Cr (0.5 M) with urease activity of 80.8 ms/cm and an optimum pH of 8.99. The bio-treatment of soil with 25% bacteria (1.2 × 109 cells/mL) and 75% Cr (0.5 M) mix ratio reduced the liquid limit (LL) of the natural soil from 36.5 to 34.2%, and the plasticity index (PI) from 16.4 to 11.6%. A microanalysis of specimens showed that the treated soil appeared more uniform and aggregated. The findings of the study show that bio-treatment with 25 Bs (1.2 × 109 cells/mL):75 Cr (0.5 M) mix ratio improved the index and physico-chemical properties of the lateritic soil considered in the study.

Significant research investigations on the characteristics of unexplored clay deposits are being conducted in light of the growing need for clay in the ceramic industry and the variable chemistry of clays. Parallel to this, the generation of waste materials like fly ash, ferrochrome slag, and silica fume is also increasing, responsible for environmental degradation. This paper aims to study the mineralogical properties of pure clays (one specimen from Siberia and five specimens from different locations in Turkey), and the effect of mentioned waste materials on the index properties of clays obtained. This study is divided into two phases, wherein in the first phase, the pure clay specimens are analyzed against mineralogical properties (i.e., chemical composition, thermal analysis, and particle size distribution). While in the second phase, index properties of pure clay specimens and clay specimens modified with 0–50% fly ash, ferrochrome slag, and silica fume are analyzed. The results reveal that the clay specimens from Turkey (USCS classification: CL) are fit for the ceramic industry and bricks production, and incorporation of waste materials can further improve their index properties. It is also observed that incorporation of 10–30% fly ash and ferrochrome slag have higher efficiency in reducing the plasticity index of clays studied as compared to the addition of silica fume. [ABSTRACT FROM AUTHOR]

This paper presents the multidisciplinary study of the southern Italy Plio-Pleistocene sediments involved in the large Montescaglioso Landslide. The principal aim of the work is to assess the compositional characters (i.e., grain-size, mineralogy, petrography and geochemistry) and some rheological features (Atterberg's limits, plasticity index and activity) of these sediments to enrich our knowledge about the Montescaglioso fine sediments and correlation among the lithological properties studied. Two types of sediments, from a deep geognostic borehole and from the surrounding landslide area, were collected and analysed. No significant compositional differences have been found between the core and landslide area sediments. Conversely, some changes have been detected in sediments along the core. Particularly, the −15 to −20 m lithostratigraphic level hosts the highest percentages of phyllosilicates and clay fraction (CF), commonly considered as possible hazard factors for the landslide triggering. Further more, in the studied core sediments, the CF contents correlate with the Atterberg's liquid and plastic limits and a CF value of about 38% was suggested as threshold value for the changing of index properties of sediments. Other factors, such as the weathering degree and clay mineral type, do not show significant correlations with the rheological properties of sediments here studied. [ABSTRACT FROM AUTHOR]

The characteristics of Soil is one of the major factors that affect flooding. This study therefore was carried out to assess the infiltration rates and index properties of soil within a flood-prone community of Oforachi in Kogi State, Nigeria using appropriate standard methods. Data obtained showed that the average soil infiltration rate ranges from 1.89 - 3.24 cm/hr and the maximum infiltration rate range between 6.00 - 9.00 cm/hr, while the soil antecedent moisture content was between 15.00 - 42.48 %. Soil infiltration properties classification based on hydraulic conductivity and sieve analysis show that soils within the study area combine silt and clay characteristics which has strong relationship with the persistent flood experienced in the area. [ABSTRACT FROM AUTHOR]

Failure of manmade embankments at the islands of Sundarban estuaries, India recur almost annually and results in the submergence of fertile agricultural land and claim human lives. Field studies were carried out to investigate the primary index properties of the embankment soil collected from three locations at the concave bends of embankment in the Sundarbans area. A correlation is drawn between alteration of natural layout of embankment soil and modification of its index properties following the traditional construction of embankment. Close introspection of embankment soil under scanning electron microscope were carried out to understand the spatial variations of the susceptibility of soil grains towards erosion for different layers of the embankment sediments. The flow velocities at permissible closest vicinity to river facing embankment wall were much higher than estimated threshold velocities for the entrainment of soil grains and resulted in the formation of undercuts at the basal part of the embankments that triggered its breaching. Finally, from the analyses of obtained results, some preventive measures are recommended to retard the rate of embankment breaching processes which may be expected to provide more sustainability to the erected embankments and will reduce the chances of frequent disasters at the Indian Sundarbans. [ABSTRACT FROM AUTHOR]

The characteristics of Soil is one of the major factors that affect flooding. This study therefore was carried out to assess the infiltration rates and index properties of soil within a flood-prone community of Oforachi in Kogi State, Nigeria using appropriate standard methods. Data obtained showed that the average soil infiltration rate ranges from 1.89 – 3.24 cm/hr and the maximum infiltration rate range between 6.00 – 9.00 cm/hr, while the soil antecedent moisture content was between 15.00 – 42.48 %. Soil infiltration properties classification based on hydraulic conductivity and sieve analysis show that soils within the study area combine silt and clay characteristics which has strong relationship with the persistent flood experienced in the area.

Shear strength parameters are essential factors in many geotechnical problems. These parameters can be obtained by laboratory tests such as the direct shear test or triaxial test and can be interpreted from field tests such as the standard penetration test and the cone penetration test. All these approaches can be considered difficult and time-consuming, especially when dealing with soils containing large-sized particles. This study investigates the application of machine learning techniques to predict the peak friction angle of granular soils based on their index properties. For this purpose, a series of medium-scale direct shear tests were conducted for different soil specimens to construct the dataset needed to explore these techniques. Index properties such as soil classification, effective particle sizes, gradation coefficients, and relative density were used as inputs for the models. The techniques were employed are linear regression, M5 tree, random forest, K-nearest neighbors, locally weighted linear regression (LWL), and artificial neural networks (ANN). It is found that the random forest, the ANN, and the LWL models could reliably predict the peak friction angle of granular soils while the other models have achieved poorer results. Also, it is put forward that picking the proper technique and fine-tuning the model hyperparameters are essential aspects to consider when applying these techniques. [ABSTRACT FROM AUTHOR]

The article presents the results of a preliminary investigation carried out to determine the effect of a small amount of potassium chloride (KCl) on the efficiency of fine slag (FS) used for treatment of expansive soil. The quantity of KCl has been varied from 0,5 to 1,5 %, while FS was varied from 5 to 15 % of the soil weight. It is found that the plasticity and differential free swell of the soil reduces with the addition of KCl as well as FS. KCl is more competent in reducing the plasticity and swelling of soil compared to FS. Whereas, the enhancement in strength and maximum dry density is relatively large in case of FS as compared to KCl added to the soil. The efficiency of fine slag to alter the properties of expansive soil increases significantly in the presence of a small quantity of KCl. The predictive models were also developed to find out the improved properties of expansive soil.