Soil Behavior Research Articles

Coupled surface-internal deformation monitoring in three-dimensional space for freezing-thawing soil

Soil frost deformation significantly influences engineering projects in cold regions. The anisotropic behavior of soil, involving surface and internal deformation in three dimensions (3D), introduces inaccuracies in evaluating freeze–thaw geological hazards. To explore the relationship between internal strain and surface displacement of soil in a 3D space during the freezing-thawing process, a platform for monitoring coupled surface-internal deformation in 3D were developed using binocular recognition technology and a novel 3D strain rosette. Subsequently, a freezing-thawing model test of soil in Dalian Offshore Airport filling is conducted using the platform. The results show that, the internal strain of soil is closely associated with the boundary conditions of the test unit. During freezing test, the vertical strain exhibits a more significant increase in comparison to the horizontal strain. Surface displacements in soil primarily occur during the initial freezing and thawing stages. The variation of surface horizontal displacement in each direction is minimal throughout the freezing-thawing process. A surface freezing boundary leads to an increment in internal strain, while the deep frozen stress relief causes the soil surface expand during thawing. This study provides a suggestion for the control of the cold source in cold region engineering.

Use of Biopolymers as Soil Stabilizers: A Review

Abstract: Soil enhancement methods offer engineers solutions for addressing stability issues encountered during project execution. Rather than employing traditional soil treatment techniques, soil stabilization focuses on enhancing the inherent characteristics of the soil. Currently, polysaccharide biopolymers like xanthan gum, guar gum, welan gum, beta glucan, and chitosan are utilized in soil behavior enhancement to mitigate environmental concerns. Biopolymers show promise in improving soil shear strength and reducing subsidence potential at varying water contents. The effectiveness of treatment relies on factors such as soil composition and the specific biopolymer used.

Numerical Analysis of Time-Dependent Strength and Stiffness in Palm Oil Fuel Ash-Stabilized Soil: Early and Long-Term Effects

Over the years, investigating the behavior of soft soil, stabilized using different techniques, has been recognized as a critical priority for geotechnical engineers. Numerous soil constitutive models have been utilized to simulate stabilized soil behavior, improve strength and ductility, and analyze load-deformation responses. However, further investigation is required to study stabilized soil's time-dependent strength and stiffness, especially at an early curing age. Early strength and stiffness development is crucial in engineering construction for improving building quality and efficiency and minimizing crack risk. Furthermore, estimating UCS from an early age aid in safety evaluation and ground-improvement analysis. Researchers are increasingly recognizing palm oil fuel ash (POFA) as an eco-friendly alternative to traditional soil stabilizers due to its abundant availability. This study proposes an advanced concrete constitutive model to simulate the time-dependent strength and stiffness of POFA-stabilized and cement-stabilized soil due to pozzolanic interactions. The model accurately measures strength and stiffness improvement from an early curing age to 28 days using finite element analysis (FEA) before then comparing the experimental results. Based on the experimental results, the UCS values of palm oil fuel ash-stabilized soil grew to 3.18 MPa and 3.89 MPa after seven and 28 days with an optimum content of 30% (POFA): 10% Magnesium Oxide (MgO). It exhibited a significant increase in early strength with 64.02% compared with cement-stabilized soil. For stiffness results, a slight increment of 9.26% was observed. Employing FEM, the sensitivity of the parameters to stress-strain behavior was investigated. Finally, the validity of the concrete constitutive model to predict the time-dependent strength and stiffness of stabilized soil was proved. Doi: 10.28991/CEJ-SP2024-010-05 Full Text: PDF

Swell-shrink and microstructural response of expansive soil treated with nanomaterials

ABSTRACT Expansive soils like Black Cotton Soil, exhibit numerous engineering hurdles due to their high swell-shrink behaviour, resulting in structural instability. Traditional stabilization techniques often prove inadequate and available nanomaterials are expensive, creating a demand for a cost-effective and eco-friendly stabilizer like nano rice husk ash (nRHA). This study tackles the challenge of stabilizing expansive soil using nRHA, synthesized via two distinct ball milling methods. Various concentrations of nRHA (0%, 0.2%, 0.4%, 0.6%, 0.8%, and 1.0%) were tested to assess their effectiveness in reducing the swell-shrink behaviour of Black Cotton Soil.r Result indicate that a 0.4% dosage of 2 + 5 hours nRHA (n 2,0.4) significantly decreases the soil’s swell-shrink potential. This treatment triggers the formation of Calcium Aluminium Oxide (CAO) and Calcium Aluminium Silicate Hydrate (CASH) gels, validated by X-ray diffraction (XRD) and Scanning electron microscope (SEM) analysis. This study advances nRHA treatments in enhancing the swell-shrink behaviour of expansive Soil.

Stabilization of Black Cotton Soil using Fly Ash

Using expansive soil at construction sites poses significant challenges due to its tendency to shrink and swell. To mitigate these issues and make expansive soil suitable for construction, proper treatment is necessary. Black cotton soils, which are expansive and have low bearing capacity, contain Montmorillonite clay mineral responsible for their shrinkage and swelling properties. Changes in moisture content can exacerbate the swelling behavior of black cotton soil. The goal of stabilization is to enhance the usability of black cotton soil for construction by adding Fly Ash (FA). Soil is a unique material, and by incorporating certain admixtures, it can be stabilized with varying percentages of Fly Ash (5%, 10%, 15%, 20%).

Induced Partial Saturation: From Mechanical Principles to Engineering Design of an Innovative and Eco-Friendly Countermeasure against Earthquake-Induced Soil Liquefaction

Earthquake-induced soil liquefaction is a catastrophic phenomenon that can damage existing building foundations and other structures, resulting in significant economic losses. Traditional mitigation techniques against liquefaction present critical aspects, such as high construction costs, impact on surrounding infrastructure and effects on the surrounding environment. Therefore, research is ongoing in order to develop new approaches and technologies suitable to mitigate liquefaction risk. Among the innovative countermeasures against liquefaction, Induced Partial Saturation (IPS) is considered one of the most promising technologies. It consists of introducing gas/air bubbles into the pore water of sandy soils in order to increase the compressibility of the fluid phase and then enhance liquefaction resistance. IPS is economical, eco-friendly and suitable for urbanised areas, where the need to reduce the risk of liquefaction must be addressed, taking into account the integrity of existing buildings. However, IPS is still far from being a routine technology since more aspects should be better understood. The main aim of this review is to raise some important questions and encourage further research and discussions on this topic. The review first analyses and discusses the effects of air/gas bubbles on the cyclic behaviour of sandy soils, focusing on the soil volume element scale and then extending the considerations to the real scale. The use of useful design charts is also described. Moreover, a section will be devoted to the effect of IPS under shallow foundations. The readers will fully understand the research trend of IPS liquefaction mitigation and will be encouraged to further explore new practical aspects to overcome the application difficulties and contribute to spreading the use of this technology.

Helicoverpa zea Boddie (Lepidoptera: Noctuidae) pupal success and adult eclosion across variable soil type and moisture.

Helicoverpa zea Boddie (Lepidoptera: Noctuidae) is an important pest in many crops in the southern United States. Upon reaching the final larval instar, H. zea quests for a pupation site in the soil. Pupae are vulnerable to mortality since their movement is limited. Soil type and moisture can influence H. zea emergence, but the interaction of these factors has not been demonstrated. We compared sandy and clay soils in greenhouse and laboratory experiments. In the first experiment, we evaluated the preference of larvae to choose either sandy or clay soil for pupation. In a second experiment, we set the sandy soils at different moisture levels and observed prepupae pupation preference in a choice scenario. In a third experiment, we observed prepupae pupation in different moisture levels in a no-choice scenario. In a 4th experiment, we evaluated adult emergence following pupation when we increased moisture or kept it constant. In a final experiment, we evaluated pupation behavior in sandy or clay soils with a webcam and a glass arena. We found that larvae preferred to pupate in sandy soils over clay soils and that pupal success was highest at intermediate moisture levels. In addition, elevated soil moisture levels did not impact the emergence of H. zea between sandy or clay soil. Finally, H. zea did not take longer to burrow in either sandy or clay soil, but the tunnels of the pupal burrow were larger in sandy soil compared to clay soil. Our results clarify H. zea behavior across soil moisture and soil type.

A Review of Chromium Behavior in Soil and its Remediation Techniques

A Review of Chromium Behavior in Soil and its Remediation Techniques

Temperature effects on adsorption and capillarity water retention mechanisms in constrained unsaturated soils

AbstractThis paper focuses on the impact of elevated temperatures on the adsorptive and capillarity water retention mechanisms of unsaturated soils under constrained (constant volume) conditions. This topic is critical for simulating the thermo-hydraulic behavior of soils in hydrogeological or geotechnical applications, including climate change effects on near surface soils, energy piles or soil borehole thermal energy storage systems in unsaturated soil layers, and buffers for geological nuclear waste repositories. A nonisothermal soil water retention curve (SWRC) that separately considers the temperature-dependency of the key parameters governing adsorptive and capillarity water retention mechanisms and soil physical parameters (e.g., surface tension, contact angle, adsorption capacity, cation exchange capacity, mean cavitation suction, air entry value and equilibrium film thickness) was developed to provide insights into the impact of temperature on water retention over the full suction range. The nonisothermal SWRC was validated using experimental data on high plasticity clays, with a good prediction of temperature effects on adsorption and capillarity water retention mechanisms in constrained unsaturated soils.

Stabilization of Expansive Soil Mixture Using Human Hair Fibre (Biopolymer)

Expansive soils sensitivity to volumetric change is one of the well-known challenges in the field of geotechnical engineering. Various attempts have been made by researchers to solve this problem. Current research presents the effect of human hair fibers on the behavior of expensive soils. A reconstituted soil of 80% kaolin as raw material and 20% bentonite with different percentages of human hair (0%, 0.5%, 1%, 1.5% and 2%) was used. The microstructure of the formulations was characterized by studying the interactions between soil and human hair using scanning electron microscopy (SEM). The microstructure of the formulations was characterized by studying the interactions between soil and human hair using scanning electron microscopy (SEM). Atterberg limits, compaction characteristics, swelling parameters, compressibility and shear strength were also examined. The results of this study indicate that the inclusion of human hair fibers significantly improves the properties of the expansive soil mixture. These results open up new prospects for the stabilization of expansive soils.

Experimental evaluation of stress history effect on compressibility characteristics of lime-stabilized expansive soils

ABSTRACT Lime stabilization has long been identified as an effective method for reducing the swelling potential of expansive soils. Despite numerous studies evaluating the volumetric behaviour of lime-stabilized expansive soils, the influence of stress history variations on deformation characteristics of these soils has not been adequately explored. This study specifically evaluates the impact of stress history conditions on compressibility characteristics of lime-stabilized expansive soils, with special attention to the rebound index at different loading stages. In this regard, one-dimensional consolidation-swell tests were conducted on samples containing different lime percentages (3% to 12%) under various stress history conditions. To include different stress history conditions, overconsolidation ratio (OCR), seating pressure, and loading step were varied during the induction of stress history in the samples. Results showed that OCR and seating pressure significantly influenced both the rebound (increased up to 118%) and compression indices (decreased up to 53%), while the loading step had a negligible impact on the compressibility properties of stabilized soils. Additionally, when comparing the relative importance of investigated parameters, it was revealed that, OCR had the highest influence on the rebound index (up to 118.0% increase), while the compression index was most significantly affected by lime percentage (up to 61.4% decrease).

The Use of Plastic Bottle Fibers in the Geotechnical Improvement of Tropical Soils from the Municipality of Viçosa - Brazil

Motivated by the environmental issues generated by the accumulation of waste from discarded plastic bottles and recognizing the utility of plastic properties in engineering, this research aimed to evaluate the application of plastic bottle fibers in the geotechnical improvement of tropical soils. In this context, the influence of quantity, roughness, and width of plastic bottle fibers on the shear strength parameters of soil- fiber mixtures, of two tropical residual soils, was analyzed. The fibers used in this study are made of Polyethylene Terephthalate (PET), generated from soft drink bottles, and added to the soil in different widths, textures, and contents. Results of the direct shear test showed higher shear strength for all soil-fiber systems compared to fiber-free mixtures. Additionally, the findings indicated that the systems with rough fibers presented better performances for clayey soil, whereas those with smooth fibers obtained better behavior for sandy soil. The cohesion results highlighted the better performance of mixtures with 0.5% fibers when compared to mixtures with 1% fibers. The enhancement of mechanical properties obtained in the studied soil-fiber systems demonstrates the potential application of these composites in geotechnical works.

Experimental investigation of the behavior of collapsible soil stabilized with calcium carbide residue

Experimental investigation of the behavior of collapsible soil stabilized with calcium carbide residue

Morphology characterization of unsaturated soils under drying-wetting cycles: crack opening and closure

AbstractThe volumetric and hydrological responses of clayey soils subjected to drying-wetting (D-W) cycles are of paramount importance for the integrity of geoenvironmental infrastructures. The study aimed to investigate the cracking behavior of clayey soils under D-W cycles by using advanced 2D imaging and 3D scanning techniques to capture the initiation and propagation of desiccation cracks within a soil specimen. The temporal variation in the soil water content and the corresponding 2D digital photography and 3D morphology of cracks were simultaneously monitored, and the cracking characteristics were interpreted. It was found that the time-dependent evaporation process was independent of the D-W cycles. Both 2D and 3D characterization showed the cracking hysteresis phenomenon in the unsaturated soil, which indicates the dependency of the crack opening and closure on the degree of saturation. D-W cycles led to the formation of subcracks and the increase in the total crack length, reflecting the soil degradation. Additionally, it was demonstrated that the 3D characterization exhibited the advantage of capturing the volumetric change and the subtle change in the macroporosity of the cracked soil over the 2D visualization. The current study provides a perspective of combining 2D and 3D characterization for interpreting the volumetric change of cracked soils and enhancing the understanding of the hydromechanical responses and the soil-atmosphere interactions.

Effect of Moisture Content and Wet–Dry Cycles on the Strength Properties of Unsaturated Clayey Sand

Based on the actual situation of the project on the Weihai–Yanhai Expressway section of Rongwu Expressway, the effects of water content change and the dry–wet cycle on the mechanical behavior of unsaturated clayey sandy soil were analyzed in this study. In this study, ventilated undrained triaxial shear tests were carried out on unsaturated clayey sandy soils with different water contents (6%, 8%, 10%, 12%, 14% and 16%). Concurrently, the soil samples were subjected to three distinct wet and dry cycle pathways (2~22%, 2~12%, and 12~22%) to gain an understanding of how the mechanical features of the soil changed under the different conditions. The test findings demonstrate that when the water content increases, the unsaturated clayey sandy soil’s cohesiveness and shear strength diminish. The strength of shear decline exhibits a pattern of first being quick, followed by sluggish. The strength of shear and cohesiveness of clayey sandy soil declined under the influence of the dry and wet cycles, with the first cycle primarily affecting variations in cohesiveness and strength of shear. Furthermore, the strength of shear and cohesiveness of clayey sandy soil diminish more with increasing wet and dry cycle amplitude and upper water content limits. Lastly, the drying shrinkage and hygroscopic expansion of clay particles in clayey sandy soils during wet and dry cycles are not significant, resulting in less structural damage and deterioration of the mechanical properties of the soils. The study’s findings have a significant impact on the durability of roadbeds made of unsaturated clayey sandy soil in both wet and dry situations.

Optimizing properties of clayey soil using lime and waste marble powder: a sustainable approach for engineering applications

Several studies have explored the potential of waste marble powder (WMP) and lime (LM) as solutions for issues associated with clayey soils. While WMP enhances mechanical properties and addresses environmental concerns, LM effectively improves soil characteristics. This research investigates the efficacy of LM and WMP, both individually and in combination, in addressing challenges specific to clayey soils in Bouzaroura El Bouni, Algeria. These soils typically exhibit low load-bearing capacity, poor permeability, and erosion susceptibility. LM demonstrates promise in enhancing soil properties, while WMP not only addresses environmental concerns but also enhances mechanical characteristics, providing a dual benefit. The study utilizes a three-variable experiment employing Response Surface Methodology (RSM) Box-Behnken Design, with variations in clay content (88%–100%), LM treatment (1.5%–9%), and WMP inclusion (1.5%–9%). Statistical analysis, including ANOVA, reveals significant patterns with p-values <5%. Functional relationships between input variables (clay, LM, and WMP) and output variables (cohesion, friction angle, and unconfined compressive strength) are expressed through high determination coefficients (R2 = 99.84%, 77.83%, and 96.78%, respectively). Numerical optimization identifies optimal mixtures with desirability close to one (0.899–0.908), indicating successful achievement of the objective with 88% clay content, 3% LM, and 6% WMP. This study provides valuable insights into optimizing clay soil behavior for environmental sustainability and engineering applications, emphasizing the potential of LM and WMP as strategic additives.

Tritium behavior in soil and mineral rock components used for plant cultivation

Immersion, percolation and tritium release experiments in peat and vermiculite soil samples were performed to analyze their behavior in this widely used medium for plant cultivation. Samples were immersed in tritiated water for 696 h and the isotope exchange capacity evaluated. A vertical flow regime was also considered with analysis for hydraulic conductivity to understand tritium mobility and therefore its availability. Peat soil showed a high tritium retention after percolation, but vermiculite seem to suppress its retention ability. The high moisture and organic content of peat enhanced its isotope exchange capacity. The falling head method was used to numerically evaluate the saturated hydraulic conductivity and outflow flux. Calculated isotope exchange capacity was 4.95×10-2 mol-T2O/g for peat and 3.38×10-2 mol-T2O/g for vermiculite. The tritium release experiment showed significant release of tritiated carbons in peat.

Numerical And Physical Modelling Of The Pore Pressure Development Around A Monopile Foundation

Offshore wind has favoured the use of monopile foundation due to its simplicity in design, construction and industrial scalability. The stability of the monopile foundations can be affected not only by the direct action of wave loads but also by the response of the surrounding seabed. Numerical and physical modelling can be used to simulate the wave-structure-seabed interaction and accurately predict the wave-induced seabed response around the monopile foundation. Within this context, a 3D coupled numerical model is developed to investigate the excess pore pressure development around a monopile foundation and the accompanying changes in the effective stress of the seabed soil. In addition to the coupled hydrodynamic-geotechnical analyses, physical model tests have been performed at the Coastal & Ocean Basin (COB) in Ostend (BE) within the SOILTWIN project in December 2023. These tests provide insight into the soil behaviour around the monopile foundation based on pore pressure measurements. The comparison of the numerical results with experimental data is essential for an improved calibration of the numerical model as well as for a better understanding of the soil response under various wave loading conditions. The experimental setup and the initial findings will be discussed during the conference.

Investigation of the contamination behavior in water and soil of an inactive dump from chemical analysis and geophysical method

In rapidly growing urban areas of developing countries, inappropriate urbanization practices near water bodies lead to significant environmental degradation, including deforestation, soil impermeabilization, and direct waste discharge into rivers and streams. This not only compromises water quality and ecosystem health but also exacerbates flood risks for nearby communities. Dumpsites, common in these regions due to inadequate waste management infrastructure, pose significant environmental threats, including soil and groundwater contamination. Our study employed a frequency-domain electromagnetic survey on an inactive dumpsite adjacent to one of Brazil’s major rivers. This geophysical method provided critical insights for geoenvironmental investigations, facilitating the collection of soil and groundwater samples to understand leachate behavior. We found that the shallower electrical conductivity map aligned with the waste disposal area's boundaries, verified by on-site surveys and excavations. Historical aerial images supported this interpretation and helped explain conductive electrical anomalies in the deeper conductivity map, linked to old irregular housing and waste disposal around the dumpsite. Moreover, the electrical conductivity maps revealed NE-oriented percolation at depth in the study area. Groundwater monitoring wells and soil analyses identified chemical elements exceeding standards set by Brazilian and international environmental agencies in this flow direction. These findings highlight the importance of using investigation techniques with superior spatial resolution compared to traditional environmental monitoring approaches. Electromagnetic methods prove effective in enhancing understanding and management of contamination in dumpsite environments.

Studying the mode shape participation factor of wave loads for offshore wind turbine structures

This paper introduces a method for analyzing resonance between Offshore Wind Turbine (OWT) structures and wave loads using Wave Participation Factor ratios (WPFs). Despite temporal fluctuations in WPFs due to wave loads, they prove effective for identifying key modes influencing wave load behavior in both fixed and floating OWT structures. For fixed OWT foundations, nonlinear soil behavior causes some natural frequency variations under wave forces, but they typically remain within a limited range. Lower natural frequency modes show minor WPFs, reducing the risk of resonance with wave loads. Modes with higher natural frequencies have substantial WPFs and are less prone to resonance. However, precautions are needed to avoid rotor-induced wind load resonance. Floating OWT structures have large WPFs in their first six near-rigid body motion modes, while mooring line stiffness leads to substantial variations in these modes. It's crucial to control the first six nonlinear frequencies outside the dominant wave load range. Beyond these six modes, natural frequencies significantly exceed wave load frequencies, reducing resonance concerns. In summary, this study presents an effective method for assessing resonance between OWT structures and loads, providing valuable insights for structural design and operational safety.