Engineering Properties Of Soil Research Articles

SPATIAL VARIABILITY OF THE GEOTECHNICAL PROPERTIES OF SOILS: A CASE STUDY OF ELIZADE UNIVERSITY

Soil variability can alter the mechanical behaviour of foundations. It is therefore, necessary to conduct site investigations specific geotechnical analysis before any construction. This study evaluated selected engineering index and properties of soils at three different locations (sites) and depths withing Elizade University (EU), Ilara-Mokin. Five soil samples were collected from each of these locations and their engineering index and properties were determined. Statistical analysis namely Analysis of Variance (ANOVA) was utilised to determine the effects of location within the campus on the selected engineering properties. The mean and standard deviation (SD) of the engineering properties of soils collected within each site were also determined. The study revealed that plastic index (Pi), liquid limit (LL), moisture content (Mc), and plastic limit (Pl) were in the range of 4 to 32, 38 to 58.5, 11.6 to 29.04 %, 20 to 42 and respectively. The engineering index of the soil and engineering properties of the soil were significantly affected by the location with F14,42 equal to 2.592212, p was 0.008673 and F14, 42 equal to 3.210318 and p was 0.001719, respectively (which are less than 0.05). The high SD also showed that the soil properties have a wide range of values within same site, this was particularly so, in the case of the Atterberg’s limits, shear strength parameters and bearing capacities. The concluded that there is variability in the soil properties within the location.

Determination of the Hydraulic Conductivity Behavior of Seaweed Added Zeolite-Bentonite Mixtures in the Presence of Temperature with Empirical Relationships

The temperature factor is of great importance in areas that directly affect the environment and engineering parameters of liners, such as solid waste storage areas. It is known that the temperature value increases as a result of the degradation of waste in these areas, and temperature changes affect the engineering properties of the soils. Properties vary depending on the soil type, and additives that can be used to improve the engineering properties of soils come to the fore. One of the most important criteria is that the additive to be used is sustainable and environmentally friendly. Zostera marina, with its terminological name, or dried seaweed an aquatic plant and is a sustainable, low-cost material used in thermal insulation. In this study, dried seaweed additive was added to zeolite-bentonite mixtures and compression parameters were determined under room temperature and 40°C. Hydraulic conductivity values of seaweed-added mixtures were determined with the help of volumetric compression coefficient (mv) and consolidation coefficient (cv) parameters and empirical relationships obtained as a result of consolidation tests. Its potential to be used as a buffer material in the presence of temperature in solid waste storage areas evaluated. The tests results showed that the seaweed additive decreased the hydraulic conductivity values of zeolite-bentonite mixtures at room temperature and under 40°C.

DEM modeling of granular soils reinforced by disposable face-mask chips

The use of disposable masks, especially in the wake of the COVID-19 pandemic, has led to an increased focus on sustainable disposal and recycling methods. This study investigates the feasibility of integrating shredded mask materials into granular soils to enhance their mechanical properties for engineering applications. After validating the selection of Discrete Element Method (DEM) contact parameters through the conducted physical experiments, a comprehensive series of DEM simulations was performed to explore the effects of various mask contents on the mechanical behavior of sand-mask chip mixtures (e.g., soil’s strength and dilatancy) under different confining pressures. Additionally, the study analyzed the potential of mask chips in improving soil fabric, reducing contact force concentrations under shearing, and contributing to the soil’s stability. The results suggest that waste face masks could serve as a valuable resource for soil stabilization. This not only provides a viable solution for mask waste management but also introduces a novel, eco-friendly material that could improve the engineering properties of granular soils. The findings underscore the importance of understanding the interaction between waste masks and soil and open new pathways for the recycling of non-biodegradable waste in geotechnical applications.

Soil-water retention capacity of expansive soil improved through enzyme induced carbonate precipitation-eggshell powder

Enzyme Induced Carbonate Precipitation (EICP) has been extensively investigated as a promising approach to improve engineering properties of soil, while Eggshell Powder (ESP) is an agricultural waste that effectively fills soil pores. The ESP provides abundant nucleation at sites for the EICP process, further promoting the effective precipitation of calcium carbonate. The research presented in this paper investigated the Soil Water Characteristic Curves (SWCC), permeability coefficient, and microstructure of expansive soil before and after EICP and EICP+ESP modification. A series of laboratory experiments were conducted, including soil water characteristic tests, permeability tests and Scanning Electron Microscopy (SEM). The results proved that the addition of EICP and EICP+ESP into natural expansive soil resulted in a gradual decline in air entry value, residual water content, and permeability coefficient, indicating an increase in water retention capacity and a decrease in permeability. Furthermore, with the intrusion of EICP and EICP+ESP, the contact between particles becomes smoother, and the soil pores become more equally distributed. Ultimately, there was an enhancement in water retention capacity of the natural expansive soil. This study emphasizes the synergistic potential of combining EICP and EICP+ESP as stabilizing additives to enhance the water retention capacity of expansive soil. Moreover, the reuse of ESP provides a sustainable solution for the resource utilization of agricultural waste and the improvement of expansive soil using bio-inspired methods.

Prediction of resilient modulus with pre-post experimental data of undisturbed subgrade soils using machine learning algorithms

The resilient modulus (MR) of subgrade, which shows relationship between stress and unit deformation of a pavement systems under traffic loads, is a design parameter of the pavement structure. Although a cyclic triaxial test apparatus can be used to directly determine the MR of the subgrade in the laboratory, utilizing prediction models based on easily obtainable soil parameters, is a more efficient method when taking time and cost considerations into account. A comprehensive laboratory testing program is designed to create MR prediction models using machine learning (ML) algorithms. 70 undisturbed soil samples are subjected to MR tests, as well as physical and engineering soil properties tests (water content, field density, specific gravity, gradation, consistency limits, unconfined compressive strength, swell pressure, swell percentage). Soil samples are drilled from a highway that has been in operation for over five years.First, a linear model like MLR is used in the study. Next, nonlinear regression models like RF, GBM, LightGBM, CatBoost, and XGBoost algorithms are used. Research findings showed that nonlinear regression models outperformed linear regression models in predicting the MR (R2 > 0.85), with the XGBoost algorithm yielding the best accuracy (R2 = 0.90). Apart from the primary effects such as confining pressure (σ3) and deviatoric stress (σd), it was found that unconfined compressive strength (qu), natural water content (wn), and swelling percentage (SR) are significant parameters in the prediction of MR among all parameters.

Improving The Geotechnical Properties of Cohesive Soils Using Portland Cement and Some Composite Polymers in A Selected Location in The City of Tanumah / Basrah Governorate – Southern Iraq

Background: The purpose of this research is to ascertain how adding Portland cement and composite polymers, as well as the ideal ratios between them, will affect cohesive soils' geotechnical characteristics. Materials and Methods: A composite polymer was created by combining three polymers—isocyanide, unsaturated polyester, polyvinyl acetate, and thinner—as well as a solvent. Portland cement was added to the soil at a rate of 5% of the sample weight. Different percentages of the weight of the cement supplied to the sample—5, 10, 15, 20, and 25%—were utilized as the composite polymer. Several geotechnical tests were carried out, including compaction, unconfined compressive strength, California bearing ratio, absorption, and Atterberg's limits, to ascertain the ideal amount of polymer for the aim of improvement. Results: The findings show that adding cement at a rate of 5% by weight of the sample and a polymeric mixture at a rate of 15% by weight of cement can improve the cohesive soil's engineering properties. It was found that the maximum dry density, unconfined compressive strength, and California bearing ratio had increased while the values of the optimal moisture content, absorption rate, liquid limit values, and plasticity index had decreased. Conclusion: The composite polymer used in soil improvement not only improves the geotechnical properties and resistance of the soil, but it also efficiently enhances and activates the effectiveness of cement. When 15% of the sample's weight of cement was composed of composite polymers, the soil's engineering attributes increased the most.

Effects of elevated temperature and treatment duration on selected index and engineering properties of lateritic soils

Lateritic soils are important to various engineering applications, especially in tropical regions, where they serve as key components in road construction, embankments, and other geotechnical structures. This study investigated the combined effects of elevated temperature and heating duration on the index and engineering properties of lateritic soils derived from two distinct parent rocks (charnockite and quartzite) in Ado-Ekiti, Nigeria. Disturbed lateritic soil samples were heated in a furnace at various temperatures (100, 200, 300, and 400 °C) for two designated durations (2 and 3 h). Standard geotechnical tests were conducted to evaluate Atterberg limits, compaction parameters, and unconfined compressive strength. The results showed that elevated temperature led to a decrease in the plastic limit, liquid limit, plasticity index, optimum moisture content (OMC), and UCS for both soils, though the extent varied between the two parent rocks. For instance, at 400 °C for 3 h, the plasticity index decreased by 47.82% for charnockite-derived soil and 55.22% for quartzite-derived soil. At the same temperature for 2 h, it decreased by 38.79% for charnockite-derived soil and 48.92% for quartzite-derived soil. Similarly, UCS decreased by 29.83% for charnockite-derived soil and 25.97% for quartzite-derived soil at 400 °C for 3 h, while at 400 °C for 2 h, UCS decreased by 21.20% for charnockite-derived soil and 23.48% for quartzite-derived soil. Conversely, maximum dry density (MDD) increased with temperature, rising by up to 20.64% for charnockite-derived soil and 14.66% for quartzite-derived soil at 400 °C for 3 h, and by 18.29% for charnockite-derived soil and 12.62% for quartzite-derived soil at 400 °C for 2 h. Longer heating durations (3 h) generally caused more pronounced changes in soil properties compared to shorter durations (2 h). For instance, OMC decreased by 13.41% for charnockite and 14.18% for quartzite at 400 °C for 3 h compared to a 2-h duration. Statistical analyses indicated that temperature had a significant influence on most properties, while the effect of heating duration was less consistent. These findings highlight the need to consider both temperature and heating duration when evaluating the engineering behavior of lateritic soils exposed to elevated temperatures. Practical implications include potential adjustments in construction practices and design parameters for road construction and embankments in regions prone to high temperatures, such as those experiencing frequent forest fires.

Assessment of the environmental impacts of utilizing coal ashes and OPC for soil stabilization applications: Leachate analysis in response to rainfall interaction

The construction industry is a leading sector for coal ashes utilization, including in cement manufacturing and soil stabilization applications. In soil stabilization, coal ashes, alongside Ordinary Portland Cement (OPC), are the most commonly used materials. However, the environmental impact of coal ashes, particularly the leaching of heavy metals from stabilized soil when exposed to rainfall, remains underexplored. There is a notable gap in assessing the environmental impacts of this utilization, particularly when the stabilized soil interacts with rainfall in real-world scenarios. Therefore, this study aimed to contribute to filling this gap. Accordingly, in this study, peat soil was stabilized by using fly ash, bottom ash, and OPC. The characterization of soil mixture materials, including physicochemical and engineering properties, was established and studied first. Following the environmental impact, simulations were conducted using a column to study soil leachate under different conditions and seasons (dry and wet) in response to its interaction with rainfall. The leachate was analyzed using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) to measure the concentrations of heavy metals, including copper (Cu), aluminum (Al), manganese (Mn), iron (Fe), and zinc (Zn). Additionally, Ion Chromatography (IC) was employed to determine the concentrations of major anions, including fluoride (F⁻), chloride (Cl⁻), nitrate (NO₃⁻), phosphate (PO₄³⁻), and sulfate (SO₄²⁻). The findings revealed the complex interaction of the chemical stabilization processes and environmental factors with the leaching behavior of heavy metals and anions, highlighting the significant impact of stabilization on leaching patterns. To conclude, this study provides a valuable contribution to understanding the environmental and engineering implications of utilizing coal ashes in soil stabilization.

Determining the Suction Capacity of Compacted Clays with Fuzzy-Set Theory

Water suction capacity is an important parameter affecting the swelling properties and volumetric change of soil. Determination of the water suction capacity is made by the experiments which are needed long time in laboratory. However, this has random errors due to the heterogeneous and anisotropic structure of soil sample together with the error caused by the operator made the experiment. Such an estimation problem, included the errors, may be easily solved with the fuzzy-set theory. In this study, the suction capacity of compacted clayey soils is predicted with the fuzzy-set theory. For this reason, the engineering properties of clayey soil (plasticity index, dry density, initial water content and suction capacity) are partitioned into fuzzy subsets, and fuzzy rules are formed. Later, a computer program in the Fortran language is written to estimate the suction capacity of compacted clayey soil from these properties. It is shown that there is a good similarity between the results of the tests and proposed fuzzy logic model.

Mineralogical and Engineering Properties of Soils Derived from In Situ Weathering of Tuff in Central Java, Indonesia

This paper presents the results of borehole investigations and laboratory tests carried out to characterize the soils derived from in situ weathering of tuff in Central Java, Indonesia. The 70 m thick weathering profile of the Quaternary tuff consisted of residual soil and completely to highly decomposed rocks. The relatively low dry unit weight and cohesion but high water content, porosity, plastic and liquid limits, and angle of internal friction of the soils in the present study were related to the dominance of halloysite clay minerals. The established relationships to predict soil shear strength parameters from the soil plasticity index and standard penetration test (SPT) N-values were examined, and linear and non-linear relationships for soils derived from in situ weathering of tuff were proposed.

Expansive clay subgrade soil improvement using municipal solid waste fly ash: Experimental and numerical approach

The expansive soil under investigation has caused damage to lightweight structures due to its swelling and shrinkage characteristics in response to changing moisture content. The study aims to assess the impact of municipal solid waste (MSW) fly ash on the engineering properties of subgrade expansive soils and its influence on pavement structure deformation. The influence of municipal solid waste fly ash on expansive soils was evaluated using laboratory tests and finite element methods. The Abaqus software was used to investigate the effects of MSW fly ash on pavement structure deformation. The input parameters employed for this analysis were elastic modulus, Poisson ratio, load, contact area dimension, and pavement layer thickness. To mitigate this issue, MSW fly ash was used as a stabilizing agent at varying percentages (5 %, 10 %, 15 %, 20 %, 25 %, and 30 % of the dry mass of the soil sample).According to the AASHTO soil classification, the soil is classified as A-7, has a high free swell, a low soaked CBR value, and a high soaked CBR swell, and does not meet the ERA manual standard for subgrade materials. The laboratory tests shown several improvements in the engineering properties of expansive soil when MSW fly ash were mixed. These improvements included a reduction of soaked CBR swelling, free swell index, plasticity index, specific gravity, optimum moisture content. Additionally, the maximum dry density and soaked CBR values increased. Numerical analysis using Abaqus software focused on vertical deformation of the pavement structure. The results showed that as the percentage of MSW fly ash in form 0 % to 25 % of soil dry weight, the vertical deformation of the pavement structure decreased from 0.84 mm to 0.67 mm. This demonstrates that the addition of MSW fly ash reduced the deformation of expansive sub-grade soil and improved the engineering qualities of pavement structure. In conclusion, the study revealed that the use of MSW fly ash as stabilizing agent effectively reduced the deformation of expansive subgrade soil and improved the engineering qualities of pavement structure.

Discussion on ‘engineering properties of clay soil stabilised with glass powder and rubber particles – a comparative study’ [geomechanics and geoengineering (2023), 1–25, DOI: 10.1080/17486025.2023.2288927]

ABSTRACT We read with great interest the recent article by Anglaaere et al. (2023). In this article, clay soil with various contents of glass powder (GP) and tyre shred particles (TSP) were subjected to direct shear and California Bearing Ratio (CBR) test, and shear strength (τ) parameters and bearing capacity were reported, respectively. Furthermore, Anglaaere et al. (2023) have performed a correlation analysis and proposed a relationship between the CBR values and τ of the samples. The results presented by Anglaaere et al. (2023) might have been useful, but there are various issues associated with this article, which we want to bring to the attention of the authors, readers, and researchers. We further emphasise that this discussion article would eliminate the dissemination of errors in the scientific knowledge presented by Anglaaere et al. (2023), and will also open new perspectives to the readers and the research fraternity.

Engineering properties of pozzolanic cement-stabilized organic soil

In this study, the engineering properties of organic soil (OS) stabilized with pozzolanic cement (PC) were investigated. In tests, 10, 15 and 20% proportions of PC were added to organic soil. Consistency limit, Proctor, unconfined compressive strength (UCS), triaxial (TA), swelling and compressibility tests were performed on the OS stabilized with PC. The addition of PC to OS increased the maximum dry density (MDD) and optimum moisture content (OMC) values. The UCS values for the OS stabilized with PC increased up to day 56 and then there was a reduction in the UCS after day 56. The internal friction angle value increased by 26% and the cohesion intercept value increased by 86% for the OS stabilized with PC. With the increase in the cement content in the OS stabilized with PC, the UCS, internal friction angle and cohesion intercept values increased. Swelling of the OS stabilized with PC rapidly reduced up to day 10, and this reduction slowed after day 10. The compressibility of the OS stabilized with PC increased up until day 10, and this increase slowed after day 10. With an increase in the cement content in the OS stabilized with PC, swelling and compressibility values reduced. As a result of the study, it appears that pozzolanic cement is an effective stabilizer for organic soil.

Strength behaviour of soil blended with two waste materials-fly ash and tire crumbs with cement

Abstract The rapid development in the economy has led to a growing need for electricity and automobiles, leading to the production of large quantities of fly ash (FA) and discarded tires. The safe disposal of these materials has become a significant problem. FA and scrap tyre derived material has some useful properties which can be beneficially used for enhancing the engineering properties of soil. Therefore, the study investigates the combined impact of FA and scrap tire-derived material on the stress-strain-strength behaviour of a fine-grained residual lateritic soil, incorporating a cementing agent. The research involves compaction tests followed by triaxial compression tests, where FA content added at an increment of 15% starting from 20% by weight of soil. The maximum FA content used in the mix is 50% by weight of soil. Tyre crumb (TC) which is a scrap tire-derived material, is also included in the study, with TC content ranging from 5% to 10% by weight. Additionally, 2% by weight of cement is added to each soil mix as a binding agent. Specimens are compacted in accordance with specific compaction parameters and subsequently cured for duration of up to 28 days. Strength tests are then carried out on those specimens to analyse their strength behaviour. This research primarily examines the shear strength characteristics of soil blended with FA, cement, and TC, emphasizing their geotechnical performance. Addition of 5% TC increases the peak deviator stress of cemented mix having 50% FA content from 1351 kPa to 2710 kPa at 300 kPa confining pressure and 28 days curing period. The inclusion of TC to soil-FA-cement blends is noted to significantly enhance shear strength when compared to mixes without tire crumb. Also, the stress-strain behaviour of soil is significantly influenced by addition of FA and cement in the presence of TC. Therefore, there is an ample scope of utilization of soil-fly ash-cement-TC mixes in geotechnical applications.

A study of bacteria producing carbonic anhydrase enzyme for CaCO3 precipitation and soil biocementation

We study the carbonic anhydrase (CA) pathway using autochthonous CA-producing bacteria as a means of inducing calcite precipitation, which acts as a biocement to improve the engineering soil properties. Forty different microbial strains producing CA were isolated from the foundation soil of a railway embankment in Prickwillow, UK. Three of the best CA-producing strains were selected and identified by DNA sequencing as Bacillus licheniformis, Bacillus toyonensis and Bacillus pumilus with CA activity values respectively of 1.79 U/ml, 1.42 U/ml and 1.55 U/ml. To optimise the treatments, we investigated the effect of pH, temperature, zinc co-factor and cementation solution molarity on the growth and CA activity and bioprecipitates, with CO2 added in the form of bicarbonate. Scanning electron microscope (SEM) analysis of the bioprecipitates showed that these had characteristic morphologies of calcite and vaterite crystals. The formation of calcite was further corroborated by FT-IR and Raman analysis of bioprecipitates. The precultured bacteria were injected into the fine-grained soil together with cementation solution. Unconfined compressive strength in treated soil increased up to 1 MPa, and its calcium carbonate content increased by 2.78%. This, as well as the stability of the treated soil upon water immersion, proved the biocementation of the fine-grained soil. These findings suggest the potential of employing the CA biocementation route for soil stabilisation pending further development of the technique.

Influence of Ground Granulated Blast Furnace Slag and Polypropylene Fibers on Engineering Properties of Clay Soil

Influence of Ground Granulated Blast Furnace Slag and Polypropylene Fibers on Engineering Properties of Clay Soil

Experimental Study on the Physical and Mechanical Properties of Modified Clay Using Xanthan Gum and Guar Gum Composite Materials

Biopolymer stabilization of soils has emerged as a viable solution for enhancing the engineering properties of soils in recent years. Xanthan gum and guar gum are two commonly used biopolymers. When combined, these materials have the ability to create stronger gels or gel strengths comparable to those achieved by using xanthan or guar gum individually, but at lower total concentrations. However, the extent of this synergistic viscosity-enhancing effect on soil improvement remains unclear. This study analyzes the effects of xanthan gum and guar gum on the physical and mechanical properties of clay under both individual and combined conditions using Atterberg limits tests, compaction tests, and triaxial consolidation undrained tests. At a 2% biopolymer content, the liquid limit of clay treated with a combination of XG and GG compounds increases by up to 8.0%, while the plastic limit increases by up to 3.9% compared to clay treated with a single colloid. With an increase in the mixing ratio, the optimal water content initially rises and then declines, peaking at 27.3%. The maximum dry density follows a pattern of initially decreasing and then increasing, with the lowest value recorded at 1.616 g·cm−3. Moreover, the shear strength of specimens treated with the XG and GG combination generally surpasses that of specimens treated with XG or GG alone. Furthermore, the combined treatment results in increased plasticity, highlighting its potential to enhance safety and stability in engineering applications.

Engineering Properties of Gypseous Soils Improved with Natural and Industrial Fibers

Engineering Properties of Gypseous Soils Improved with Natural and Industrial Fibers

An experimental investigation on the effect of vetiver grass root system on the engineering properties of soil

An experimental investigation on the effect of vetiver grass root system on the engineering properties of soil

A review on Comparative study of using Silica Fume and Areca Fiber on Soil Stabilization

Abstract The rapid expansion of urban areas and the rise in construction activities have led to a shortage of land with suitable soil conditions. This has forced people to utilize weak soils available locally for construction purposes, employing various stabilization techniques. Urban expansion and construction demand the utilization of local weak soils for building, necessitating the application of soil stabilization techniques. These methods enhance soil strength by altering its properties. This study evaluates silica fume and areca fiber as stabilizers. Silica fume is a pozzolanic and supplementary cementitious material that enhances material properties such as strength, durability, and resistance to chemical attacks and abrasion. Few studies have examined areca fiber as soil reinforcement. Areca fiber (20-30 mm in length) upto 0.6% of dry weight of soil significantly improves engineering properties of soil. Varied weight ratios of silica fume and areca fiber are used based on soil type for optimal conditions. Silica fume stabilizes, and areca fiber reinforces problematic soil, as demonstrated through compaction, UCS, and CBR tests. Utilizing such waste materials is a cost-effective and more sustainable approach in the field of engineering. This research investigates the compaction and strength properties of various problematic soils stabilized with silica fume and areca fiber, providing a comprehensive review of the findings.