Soil Mechanics Research Articles

Effect of salinization on soil properties and mechanisms beneficial to microorganisms in salinized soil remediation–a review

Salinized soil is an important reserved arable land resource in China. The management and utilization of salinized soil can safeguard the current size of arable land and a stable grain yield. Salt accumulation will lead to the deterioration of soil properties, destroy soil production potential and damage soil ecological functions, which in turn will threaten global water and soil resources and food security, and affect sustainable socio-economic development. Microorganisms are important components of salinized soil. Microbial remediation is an important research tool in improving salinized soil and is key to realizing sustainable development of agriculture and the ecosystem. Knowledge about the impact of salinization on soil properties and measures using microorganisms in remediation of salinized soil has grown over time. However, the mechanisms governing these impacts and the ecological principles for microbial remediation are scarce. Thus, it is imperative to summarize the effects of salinization on soil physical, chemical, and microbial properties, and then review the related mechanisms of halophilic and halotolerant microorganisms in salinized soil remediation via direct and indirect pathways. The stability, persistence, and safety of the microbial remediation effect is also highlighted in this review to further promote the application of microbial remediation in salinized soil. The objective of this review is to provide reference and theoretical support for the improvement and utilization of salinized soil.

Impacts of geography, climate, soil properties and vegetation characteristics on soil C:N:P stoichiometry across the Qinghai-Tibetan Plateau

Soil C:N:P (soil organic carbon: total nitrogen: total phosphorus) stoichiometry can give important information about biogeochemical cycling in terrestrial ecosystems. The spatial patterns and driving mechanisms of soil C:N:P stoichiometry are still poorly understood on the Qinghai-Tibetan Plateau. In this study, we therefore combine data on the geographic position, climate, soil properties and vegetation characteristics of 319 sites across the plateau to investigate their relationship with the horizontal and vertical patterns of soil C, N and P concentrations and the C:N:P ratios. We observed higherSOC (30.5–46.8 mg g-1), TN (2.4–3.4 mg g-1), C:N (14.7–18.0) and N:P (6.9–8.0) in alpine meadows, forests and shrublands, and higher TP (1.6 mg g-1) in croplands. Overall, SOC, TN, TP, C:N and N:P showed decreasing trends with an amplitude of 67%, 64%, 19%, 12% and 54% respectively along the soil profile. Soil cation exchange capacity (CEC) and bulk density were the stronger environmental drivers of SOC and TN. Soil TP showed latitudinal and longitudinal increasing trends in all soil layers. Soil properties explained most of the variations in SOC (67%–90%), TN (67%–87%), C:N (61%–89%) and N:P (64%-85%), with increasing impacts along the soil profile. Geographical position and climate influenced TP both directly and indirectly through soil properties, with geographical position being the predominant driver (46%–65%) along the whole soil profile. The variation in soil C:N was mostly driven by SOC and TN, and the direct and indirect effects of the environmental factors were relatively weak. Geographical position, climate factors, soil properties and vegetation indirectly impacted soil N:P through their effects on soil TN and TP in all the soil layers. Altogether, our findings shed important light on the relative contribution of geography, climate, vegetation and soil properties on soil C:N and N:P, thus providing a better understanding of C, N, and P cycling across the Qinghai-Tibetan Plateau.

Analysis of tough clay soil plastic index from several quarries in Aceh Besar District for seismic mitigation

Abstract Clay soils that tend to have the potential for landslides and earthquake-induced cracking are a serious problem in the development of infrastructure and settlements in the area. This research investigation sample was collected at a quarry in several areas of Aceh Besar District to identify problematic soil behavior in various quarries. The method used was stabilization by conducting compaction testing to obtain the optimum moisture content of the natural soil. The quarry soil samples taken were disturbed samples, which were then tested directly at the Soil Mechanics Laboratory. The data used in this study is the plastic index (PI) value. This research aims to assess stabilization strategies for problematic clay soils as an earthquake risk mitigation effort in the Aceh Besar region. The results of this study are expected to provide practical guidance for stakeholders in planning and developing more earthquake-resistant infrastructure in Aceh Besar. The result of the test showed that the OMC value was 36.3% with a dry weight of 1.22 gr/cm3.

Study on salt-frost heave characteristics, improvement effect, and curing mechanism of loess-like sulphate soil

Aiming at the obvious salt-frost heave disease of loess-like sulphate soil in seasonal frozen areas, the compaction characteristics, salt-frost heave property and improvement effect of saline soil treated by adding lime, silica fume and lime-silica fume mixture are investigated. The results show that the salt-frost heave and collapse occur alternately and periodically with the freeze-thaw process. In addition, the peak salt-frost heave and thawing residual salt-frost heave increases with the increasing salt content, and the salt-frost heave shows obvious linear accumulation. The composition and dosage of the curing agent, freeze-thaw times and maintenance time have a significant influence on the improvement effect of salt-frost heave. The improvement effect of the lime-silica fume mixture far exceeds that of lime or silica fume alone. Moreover, repeated freeze-thaw cycles have a significant deteriorating effect on reducing salt-frost heave, and the salt-frost heave decreases with increasing maintenance time. The mechanism of curing saline soil by lime-silica fume mixture mainly includes physical filling effect and pozzolanic reaction effect. In particular, the strong pozzolanic reaction between lime and silica fume produces cementing material (CSH), effectively cementing the soil particles and substantially inhibiting the salt-frost heave.

Internal variable gradient model for active earth pressure of rigid retaining wall moving with translation

The instability of retaining wall is a key factor for many geo-hazards, such as landslides. To estimate the stability of retaining wall, the distribution of earth pressure is necessary. The results of in-situ observations and indoor experiments demonstrate that the distribution of earth pressure behind the retaining wall exhibits remarkable nonlinearity. When the results are analyzed in details, the oscillation and quasi-periodicity of the distribution of earth pressure are observed, which has not been given widely concerns and cannot be described by the existing analytical models. Based on the internal variable gradient theory and operator averaging method, a gradient-enhanced softening constitutive model is proposed in this paper to describe the oscillation and quasi-periodicity of the distribution of earth pressure acting on the retaining wall, by introducing the high-order gradient terms of the hydrostatic pressure into Mohr-Coulomb yield condition. In order to check the applicability of the proposed formulation, the predictions from the formulations are compared with the full-scale and laboratory-scale test results as well as the existing formulations. It is noted from the comparisons between predicted and measured values that the results of gradient-dependent softening constitutive model provides the comparable approximations for active earth pressure and describes the oscillation and quasi-periodicity very well. This model may enhance the comprehension of soil mechanics and provide a novel view for the design of the retaining wall.

Biochar-bacteria-plant combined potential for remediation of oil-contaminated soil.

Oil pollution is a common type of soil organic pollution that is harmful to the ecosystem. Bioremediation, particularly microbe-assisted phytoremediation of oil-contaminated soil, has become a research hotspot in recent years. In order to explore more appropriate bioremediation strategies for soil oil contamination and the mechanism of remediation, we compared the remediation effects of three plants when applied in combination with a microbial agent and biochar. The combined remediation approach of Tagetes erecta, microbial agent, and biochar exhibited the best plant growth and the highest total petroleum hydrocarbons degradation efficiency (76.60%). In addition, all of the remediation methods provided varying degrees of restoration of carbon and nitrogen contents of soils. High-throughput sequencing found that microbial community diversity and richness were enhanced in most restored soils. Some soil microorganisms associated with oil degradation and plant growth promotion such as Cavicella, C1_B045, Sphingomonas, MND1, Bacillus and Ramlibacter were identified in this study, among which Bacillus was the major component in the microbial agent. Bacillus was positively correlated with all soil remediation indicators tested and was substantially enriched in the rhizosphere of T. erecta. Functional gene prediction of the soil bacterial community based on the KEGG database revealed that pathways of carbohydrate metabolism and amino acid metabolism were up-regulated during remediation of oil-contaminated soils. This study provides a potential method for efficient remediation of oil-contaminated soils and thoroughly examines the biochar-bacteria-plant combined remediation mechanisms of oil-contaminated soil, as well as the combined effects from the perspective of soil bacterial communities.

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.

A Novel Calculate Model of Shear Deformation and Relative Displacement of Pile–Soil Interface in Warm Frozen Soil Foundation

In permafrost regions with warm frozen soil, the pile foundation is commonly used, but most currently available models for the WFS foundation pile–soil system are either highly empirical or overcomplicated, without a simplified theoretical manner in engineering. This study derives a novel and simplified calculated model of the WFS pile–soil system. The model is formulated in terms of the shear deformation theory and load transfer method based on the rigorous deformation mechanism of the WFS foundation soil around the pile. Considering the different depth soil features and the equilibrium state of the pile–soil system, dividing warm frozen soil foundation into three regions (TPPR, ER, and BPPR) to calculate the Dp and Ds can simply obtain the total displacement of pile under different loads. The results demonstrate that the present theoretical model can well predict the WFS foundation load–displacement response of the pile. The present model provides a simple, practical, and effective approach for the estimation of the load–displacement behavior of piles installed in the WFS foundation.

Triaxial Test and Discrete Element Numerical Simulation of Geogrid-Reinforced Clay Soil

Indoor triaxial tests on geogrid-reinforced clay elucidate the macroscopic changes in soil strength indices post-reinforcement, yet the underlying mechanisms of strength enhancement require further investigation. By conducting indoor triaxial tests and establishing a corresponding discrete element numerical model, we can delve into the fine-scale mechanisms of geogrid-reinforced soil. This includes analyzing changes in fine-scale parameters such as porosity, the coordination number, and contact stress between soil particles. The findings suggest that an increase in the number of geogrid reinforcement layers leads to a more pronounced improvement in peak strength and cohesion, albeit with minimal impact on the internal friction angle of the specimens. Furthermore, analysis of the triaxial test curves of reinforced soils indicates that the stress–strain relationship adheres to the Duncan–Chang model. Parameters derived from this model have been validated against experimental data, confirming their accuracy. The discrete element model was used to analyze the variations in fine-scale parameters such as porosity and coordination number. It revealed that reinforcement reduces the fluctuation amplitude of porosity and significantly increases the number of particle contacts, resulting in a denser soil structure. Further analysis of the change in contact stress between particles in the discrete element model revealed that the contact force between particles increased significantly after reinforcement and that the reinforcement played a role in restraining the soil particles and dispersing the reinforcement stress, which explains the increase in the strength of the mesh-reinforced clays from another perspective. This further elucidates the strength enhancement mechanism in geogrid-reinforced clay, offering a new perspective on the mechanical behavior and strength development of such materials.

Bearing Capacity Characteristic Analysis of Anti-floating Bolts in Unsaturated Soil Based on Mindlin Solution

AbstractBased on Mindlin solution and the theory of unsaturated soil mechanics, the theoretical solutions of shear stress and axial force distribution in the elastic stage of full-length binding-type anti-floating bolts were derived, and the bearing capacity characteristics of such bolts and the influencing factors were analyzed. In this paper, the design parameters of anti-floating anchor in a negative two-floor basement of a commercial square are substituted into the formula derived in this paper. The results show that, in unsaturated soil, the shear stress and axial force of the full-length bonded anti-floating anchor are distributed along the total length of the anchor, but neutral points appear in both of them, which is mainly due to the reduction of the axial force and shear stress of the anti-floating anchor caused by the matric suction. The formula derived in this paper is used to analyze the factors affecting the bearing capacity of anti-floating anchor bolt in unsaturated soil. The results show that: the greater the elastic modulus of soil mass, the greater the peak value of shear stress curve, the closer the peak value is to the head of anchor bolt, and the greater the axial force decline rate. With the increase of anchor solid diameter D, the peak value of shear stress decreases, the peak value moves backward, the neutral point moves forward, the negative shear stress value increases, the decline rate of axial force distribution curve decreases, but the negative axial force increases. With the increase of the additional shear stress τ0, the peak value of the shear stress curve decreases, the peak value moves to the hole of the anchor rod, the neutral point moves to the hole, the negative shear stress increases, the decline rate of the axial force distribution curve increases, and the negative axial force increases.

Analytical and experimental evaluation of two-layered unsaturated sand bearing capacity

Pavement design methods based on principles of unsaturated soil mechanics take into account high soil shear strength due to matric suction resulting in more economical design especially in long roads. In this study, the bearing capacity of two-layer unsaturated sand was investigated using both analytical and experimental methods. At first, using the limit equilibrium method an analytical formula was proposed to determine the bearing capacity of two-layer unsaturated sand in which linear suction profile was considered in soil layers. It should be considered that the constant matric suction distribution assumed by the previous researchers does not show the real profile of matric suction within the soil, sometimes resulting in miscalculated unsaturated bearing capacity. Also, the bearing capacity of two-layer unsaturated poorly graded sand was investigated experimentally in different suctions by a special unsaturated chamber apparatus (UCA) designed for this purpose. The results show more than double increase of unsaturated soil bearing capacity with Sr = 25% compared to saturated soil. The formation of failure wedges in all experiments was investigated by image processing. An acceptable agreement was obtained between the theoretical and experimental bearing capacity results.

Microbiological Mechanisms of Collaborative Remediation of Cadmium-Contaminated Soil with Bacillus cereus and Lawn Plants.

Severe cadmium contamination poses a serious threat to food security and human health. Plant-microbial combined remediation represents a potential technique for reducing heavy metals in soil. The main objective of this study is to explore the remediation mechanism of cadmium-contaminated soil using a combined approach of lawn plants and microbes. The target bacterium Bacillus cereus was selected from cadmium-contaminated soil in mining areas, and two lawn plants (Festuca arundinacea A'rid III' and Poa pratensis M'idnight II') were chosen as the target plants. We investigated the remediation effect of different concentrations of bacterial solution on cadmium-contaminated soil using two lawn plants through pot experiments, as well as the impact on the soil microbial community structure. The results demonstrate that Bacillus cereus promotes plant growth, and the combined action of lawn plants and Bacillus cereus improves soil quality, enhancing the bioavailability of cadmium in the soil. At a bacterial suspension concentration of 105 CFU/mL, the optimal remediation treatment was observed. The removal efficiency of cadmium in the soil under Festuca arundinacea and Poa pratensis treatments reached 33.69% and 33.33%, respectively. Additionally, the content of bioavailable cadmium in the rhizosphere soil increased by up to 13.43% and 26.54%, respectively. Bacillus cereus increased the bacterial diversity in the non-rhizosphere soil of both lawn plants but reduced it in the rhizosphere soil. Additionally, the relative abundance of Actinobacteriota and Firmicutes, which have potential for heavy metal remediation, increased after the application of the bacterial solution. This study demonstrates that Bacillus cereus can enhance the potential of lawn plants to remediate cadmium-contaminated soil and reshape the microbial communities in both rhizosphere and non-rhizosphere soils.

A new experimental setup for the determination of drying soil–water characteristic curve and coefficient of permeability using the continuous evaporation method and osmotic tensiometers

Soil-water characteristic curve (SWCC) and coefficient of permeability (k) are amongst the most crucial soil properties in unsaturated soil mechanics for soil moisture conservation. The direct measurement and prediction of such properties are important to engineering applications, but they are complicated. This study developed a new experimental setup (the OT permeameter) using osmotic tensiometers (OTs) and the continuous evaporation method. The proposed OT permeameter could directly measure SWCC and k up to 1000 kPa suction within one to two weeks. Moreover, the proposed setup is fully automated and data processing was minimal. In addition, a new general equation has been developed to predict and best fit the unsaturated k measurement. The proposed equation uses a minimal number of parameters that carry physical meaning and provides an intuitive and easy way to predict and best-fit k measurement. The accuracy and robustness of both the proposed OT permeameter and prediction equation were evaluated using published data and experimental data from this study.

Unsaturation triggers specific adsorption performance of water films in the clay nanopores

Soil is typically unsaturated, with water films covering the soil particles playing a crucial role in soil mechanics, structure, and element transport. However, the unusual behavior of these water films and the underlying mechanisms are not yet fully understood. This study, which used molecular dynamics methods, sheds light on the distinct interactions between water films and clay surfaces under unsaturation. At the water-mineral interface, water molecules formed a layered structure, while they rearranged as a meniscus as the unsaturation extent increased. On the other hand, unsaturation had a significant impact on the location of water molecules at the water-vapor interface, but only a limited effect at the water-mineral interface. The water’s orientational ordering and hydrogen bonding interactions were significantly affected by changes in relative humidity (RH). Based on the distance-dependent diffusion coefficient, the water molecules within the water film were classified into three types: WT1 (< 5 Å) had faster diffusivity at higher RH, WT2 (5–6 Å) had comparable diffusivity at any RH, and WT3 (> 6 Å) had faster diffusivity at intermediate RH. This classification was supported by the retention dynamics analysis. The specific behaviors mentioned above, which are associated with unsaturation, are closely linked to Na+ hydration. This is because the interaction between water and Na+ is more pronounced than the interaction between water and minerals or Cl−. The results indicate that unsaturation triggers specific adsorption behaviors of water films that cover the clay surfaces. These behaviors should be considered in interfacial processes and environmental engineering.

Recovery of Rare Earth Elements from Ion-Adsorption Deposits Using Electrokinetic Technology: The Soil Conductivity Mechanism Study

Rare earth elements (REEs) are essential raw materials for modern industries but mining them has caused severe environmental issues, particularly the recovery of heavy REEs (HREEs) from ion-adsorption deposits (IADs). Very recently, an emerging technology, electrokinetic mining (EKM), has been proposed for the green and efficient recovery of REEs from IADs. However, the conduction mechanism of the weathering crust soil, which is also a prerequisite for EKM, remains unclear, making the EKM process unpredictable. Here, we systematically investigated the conductivity of weathering crust soil in the presence of light REEs (LREEs, i.e., La3+ and Sm3+) and HREEs (Er3+ and Y3+), respectively. Results suggested that the voltage was dynamically and spatially redistributed by the movement of REEs and water during EKM, and the conventional assumption of the linear distribution of voltage leads to an inaccurate description of soil voltage. We proposed an improved Archie’s equation by coupling the mechanisms of liquid phase and solid-liquid interface conduction, which can predict soil conductivity more precisely. Moreover, the extended Archie’s equation is able to recalculate the voltage distribution at distinct times and spaces well during EKM. More importantly, the water content in field-scale weathered-crust soils can be retrieved by the newly proposed Archie’s equation, which helps optimize the leaching wells and improve the recovery rate of REE. This study focuses on the conduction mechanism of weathering crust soil, which provides a theoretical basis for better use of the EKM technology and promotes mining efficiency fundamentally.

Bearing capacity of shallow foundations: a focus on the depth factors in combination with the respective N-factors

The ongoing refinement of bearing capacity equations remains pivotal in soil mechanics and foundation engineering, reflecting its critical role in ensuring design efficacy and construction safety. This study conducts a thorough evaluation of classical bearing capacity methods—Terzaghi, Meyerhof, Vesic, and Hansen—and methods included in various design standards, such as EN1997:2004, prEN1997:2023, GEO, AASHTO, FHWA, and API. It explores the performance and applicability of these approaches, identifying areas for potential improvement. In response to identified challenges, the paper proposes the integration of a unified depth factor. This new factor is designed to be applicable across all N-terms, providing a more versatile and accurate tool for bearing capacity predictions. Unlike the original depth factors unique to each method, which may not fully address complex soil and footing conditions, the unified depth factor is developed to enhance prediction accuracy for a wide range of conditions, including both flexible and rigid footings under varying flow rules (ψ = 0 and ψ = φ). This depth factor corrects for modeling errors, emphasizing the importance of pairing the correct set of N-factors with their corresponding depth factor. By offering a singular depth factor that aligns with the outcomes of finite element analysis, this paper not only simplifies the computational process but also enhances the accuracy of bearing capacity predictions across a diverse range of soil conditions and footing types. The comparative analysis, based on finite element analysis, validates the proposed method’s effectiveness, showcasing its potential to significantly refine foundation design practices by comparing it with both traditional and newly developed depth factors.

Soil mechanics principles for modelling railway track performance

Predicting the performance of railway track is difficult owing to the complex and repeated nature of the loading, the many millions of cycles applied over the life of the structure, the need to characterise the often-infinitesimal rate of accumulation of plastic settlement, and the importance of differential settlements in the along-track direction, which can adversely impact train ride and passenger comfort. These come in addition to the usual soil mechanics challenges of reproducing in a constitutive model the real behaviour of soil and soil-like materials such as railway ballast. Degradation of the geomaterials comprising the trackbed and the underlying ground or earthwork owing to mechanical and environmental effects is a further concern. The paper discusses these issues and explores the application of fundamental soil mechanics principles and advanced constitutive models to understanding and quantifying their effects on railway track and trackbed performance. Recommendations for future research are made.

A framework for estimating the matric suction in unsaturated soils using multiple artificial intelligence techniques

AbstractImplementation of the state‐of‐the‐art understanding of the mechanics of unsaturated soils into geotechnical engineering practice is partly limited due to the lack of quick, reliable, and economical techniques for matric suction measurement. Matric suction is one of the key stress state variables that significantly influences the hydro‐mechanical behavior of unsaturated soils. In this paper, to address this objective, two artificial intelligence (AI) models were developed for estimating matric suction in unsaturated soils based on the particle swarm optimization support vector regression (PSO‐SVR) and multivariate adaptive regression spline (MARS) algorithms. The results suggest that both these models can reasonably estimate matric suction. Compared to the MARS model, the PSO‐SVR model can achieve higher accuracy. Nonetheless, the MARS model facilitates the sensitivity analysis and the selection of essential inputs. A novel integrated framework is proposed and validated, leveraging the strengths, and alleviating the limitations of the PSO‐SVR and MARS algorithms for reliable and rapid estimation of matric suction in the range of 0–1500 kPa for low plastic soils (0 &lt; Ip ≤ 7). Six inputs are required to use this model successfully; some can be measured using conventional laboratory tests, and others can be calculated from mass‐volume relationships.

Finite Element Analysis of Combined Bearing Characteristics of Pile–Soil Interaction in Composite Foundation

Composite foundations have been widely used and promoted in practical engineering applications. However, research on the joint-bearing mechanism of piles and soil within composite foundations is still not comprehensive enough. This paper proposes a method for calculating the additional internal forces of piles and soil within composite foundations. Based on a three-dimensional finite element analysis, this study investigates the variation patterns of the stress, displacement, and additional internal forces of piles and soil in the depth direction under the action of upper loads when using friction piles and end-bearing piles. This research aims to reveal the bearing performance of piles and soil. The results showed that, under the same conditions and due to the presence of end-bearing effects, the internal forces experienced by the entire pile body of the end-bearing piles were more uniform, exhibiting significant advantages in resisting deformation and being able to withstand larger loads. Additionally, the diffusion mechanism of the vertical forces, stresses, and displacements of piles and soil is discussed. Due to the negative frictional resistance of soil and the influence of pile end-bearing effects, the distribution of internal forces and the displacements of piles and soil exhibited different characteristics. This study provides a scientific reference for the theoretical analysis and design of composite foundations.

Enhancing Soil Resilience to Climatic Wetting‐Drying Cycles Through a Bio‐Mediated Approach

AbstractClimatic wetting‐drying cycles exacerbated by climate change can trigger several weakening mechanisms in surface soils, potentially leading to instability and failure of slopes and earthen structures. This study proposes a bio‐mediated approach based on microbially induced calcite precipitation (MICP) to increase soil resilience to wetting‐drying cycles. To explore its viability and the underlying mechanisms, we conducted a series of laboratory tests on clayey soil that underwent six wetting‐drying cycles. The tests were conducted with different treatment methods to investigate the effect of treatment sequence and cementation solution concentration. After MICP treatment, the initial evaporation rate, surface crack ratio during drying, and total soil weight loss during rainfall erosion were reduced by up to 32%, 85%, and 90%, respectively. Spraying the cementation solution first in the MICP treatment sequence proves more effective in improving soil water retention capacity. On the other hand, initiating the sequence with the bacterial solution demonstrates a more pronounced effect in reducing soil desiccation cracks and erosion. Microstructure analysis reveals that the content and distribution of CaCO3 precipitation are the major factors controlling the effectiveness of MICP for the cementation of clayey soil. Employing MICP can minimize the carbon footprint and contribute to developing environmentally friendly solutions for soil improvement in regions affected by climatic wetting‐drying cycles.