Soil desiccation cracks and crack networks significantly influence the mechanical properties of soils. Accurate modeling and prediction of crack development are essential for both laboratory research and practical applications in geotechnical engineering and environmental science. In this study, a Desiccation Crack Simulation Program (DCSP) was developed on the MATLAB platform to simulate the evolution of soil desiccation cracks. Based on comprehensive statistical analyses of crack network images from previous studies and detailed observations of crack propagation, we propose a stochastic crack network generation model informed by geometric parameters and crack development processes. The model encompasses five key steps: (1) selection of crack initiation points, (2) crack propagation and intersection, (3) termination of crack growth, (4) secondary crack generation, and (5) final network formation. Key parameters include crack step size, randomized propagation direction, number of initial development points, and crack attraction distance. The DCSP enables both the rapid generation of random crack networks and the prediction of partially developed networks. The program was validated using two soil types, Xiashu soil and Pukou soil, demonstrating its effectiveness in simulating crack evolution. Prediction accuracy improves as crack network develops, highlighting the model's potential for predicting soil desiccation crack patterns.

The presence of desiccation cracks can affect rainfall-induced slope stability through both hydraulic and mechanical ways. Despite the valuable insights gained from physical tests in literature, there still lacks understanding how crack characteristics impact water flow dynamics and slope stability, especially considering the coexistence of vegetation. In this study, new analytical solutions were derived for calculating pore-water pressure and slope stability for an infinite unsaturated slope with cracks and vegetation. Both enhanced infiltration from water-filled cracks and water uptake by plant roots are considered. Using the newly developed solutions, two series of parametric analyses were carried out to improve understanding of the factors affecting crack water infiltration and hence the stability of vegetated slope. The calculated results show that slope failure at shallow depths is governed by the surface crack ratio, whereas deeper failures typically occur with greater crack depths. The surface crack ratio primarily influences the hydraulic response at shallow depths not exceeding 1.5 m, hence affecting the factor of safety for slip surfaces within the crack zone. Moreover, increasing the crack-to-root depth ratio from 0.5 to 1.5 results in a 25% reduction in suction at 1.5 m, threatening slope safety in deeper depth after 10-year rainfall.

Soil desiccation cracking, a natural phenomenon involving the complex interaction of multi-physical fields, significantly weakens the mechanical and hydraulic properties of soil, potentially leading to natural hazards. This study proposes a coupled thermo-hygro-mechanical peridynamic (PD) model to investigate the mechanical responses and fracture behaviors in saturated soils due to moisture evaporation and heat transfer. Specifically, the temperature-dependent moisture diffusion and moisture-dependent heat conduction equations are nonlocally reformulated using peridynamic differential operators (PDDO). The constitutive model incorporates the spatial attenuation of nonlocal interactions and the effects of moisture and temperature in the bond-based peridynamic framework. Utilizing a hybrid explicit-implicit solution strategy, the model can effectively capture soil strip detachment, cracking, and curling. The model is also employed to explore moisture transmission mechanisms, evaluate the effects of temperature and thickness on crack morphology, and reveal the relationship between stress, strain evolution, and crack propagation. Furthermore, the model incorporates the reference evapotranspiration formula, which can account for environmental factors such as solar radiation, ambient temperature, relative humidity, and wind speed. Therefore, this expands the scope of model applicability and enables the simulation of soil desiccation cracking under natural conditions.

Desiccation crack patterns are commonly observed in natural and engineered soils and provides preferential pathways for moisture infiltrating into the soil. Cracks occur easily in soil when moisture is lost due to desiccation. Crack formation and development are closely related to moisture content and have a marked impact on the soil deformation characteristics and hydraulic properties. However, the critical moisture content below which desiccation cracks appear in the soil is usually determined by experiment because there is a lack of research on theoretical calculation models. Therefore, a theoretical calculation model is proposed to calculate the critical moisture content, and a parameter, lambda\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\lambda$$\end{document}, based on the following relationships: between soil grain size and suction, between suction and tensile strength, and between soil cracking and tensile strength. The critical moisture content values of different grain compositions were calculated and compared with laboratory experiments of desiccation crack. The critical moisture content of the granite residual soil is between 20% (50% liquid limit) and 30% (75% liquid limit). The presented model provides a means to estimate the critical moisture content of crack formation from soil desiccation using basic soil properties. This method can estimate the characteristics of soil desiccation cracks under extreme weather condition.

This study investigates the role of polypropylene fibers (PFs) in mitigating the combined effects of wet-dry (W-D) cycles and vibration event (VE), such as earthquake or machine vibrations, on the desiccation cracking and mechanical behavior of clay through model tests. A comprehensive experimental program was conducted using compacted clayey soil specimens, treated with various PF percentages (i.e., 0.2 %, 0.4 %, 0.6 %, and 0.8 %) and untreated (i.e., 0 % PF). These specimens were subjected to multiple W-D cycles, with their behavior documented through cinematography. Desiccation cracking and mechanical responses were evaluated after each W-D cycle and subsequent VE. Results indicated that surface cracking, quantified by morphology and crack parameters i.e., crack surface ratio (Rsc), total crack length (Ltc), and crack line density (Dcl), increased with progressive W-D cycles. Higher PF content in soil significantly reduced desiccation cracking across all W-D phases, attributable to the enhanced tensile strength and stress mitigation provided by the fibers. Following VE, surface crack and fragmentation visibility decreased due to the shaking effects, as indicated by reductions in Rsc and Dcl. However, Ltc increased slightly, suggesting either crack persistence or lengthening. Higher PF content resulted in a more substantial reduction in Rsc and Dcl and a reduced increase in Ltc after VE. W-D cycles led to increased cone index (CI) values, reflecting enhanced compactness due to shrinkage which enhances with PF content showing improved soil resistance to loading. Meanwhile, VE reduced CI values following W-D cycles, particularly in nearsurface layers, PF content mitigates this reduction, demonstrating that PF contributes to a more stable soil matrix. Also, PF content decreased the soil deformation under W-D cycles and subsequent VE.

Climate-induced desiccation cracks exhibit a hysteresis behavior, referred to as crack dynamic hysteresis (CDH), where they display different geometric characteristics during the drying and wetting phases at constant soil water content. This phenomenon has a complex effect on slope stability, an aspect often overlooked in analytical and numerical methods. In this study, we conducted experimental and numerical analyses to provide new insights into the effects of the CDH on slope stability. A series of laboratory experiments on desiccation cracking under drying-wetting cycles were performed. The testing results were used to develop and validate an extended dynamic dual-permeability model. The proposed model was integrated into a set of slope stability analyses using the finite element method. The numerical model results show that CDH causes greater fluctuations in crack dynamics and increases soil water retention under drying-wetting cycles. Neglecting this phenomenon leads to underestimation of slope stability during dry conditions and overestimation during wet conditions, with these discrepancies becoming more pronounced as the cycles progress. Furthermore, CDH changes the mechanical properties of soil, transitioning relatively stable zones to regions prone to localized instability. These unstable zones present significant challenges for accurately analyzing and managing slopes with cracked soil layers. Monitoring groundwater fluctuations and local crack development after heavy rainfall events is essential for mitigating localized slope collapses.

The presence of cracks significantly impacts the hydrological behaviour of clay embankments. This study aimed to enhance understanding of the complex interplay between the amount and propagation of desiccation cracks and seasonal variations. A full-scale embankment was constructed and equipped with an array of instruments, including pore water pressure, volumetric water content (VWC), and crack observer. The results suggested that continues cracks at shallow depths (0.5 m) exhibit significant seasonal fluctuations due to pronounced soil-atmosphere interactions, facilitating rapid water movement and substantial changes in crack width. In contrast, discontinuous cracks at intermediate depths (0.5 m) are less affected by seasonal changes, but they can propagate and connect over time due to repeated wetting and drying cycles. The crack intensity factor (CIF) above 0.4 m is highly sensitive to climatic variations, leading to pronounced fluctuations with changes in rainfall and dry conditions. The twofold increase in CIF values leads to a significant reduction in VWC (by 13.5%) at the depth of 0.25 m under the same atmospheric water balance. However, this effect is less pronounced at greater depths, such as 0.5 m, as discontinuous cracks are less effective in facilitating rapid drainage and moisture loss.

Desiccation cracking has a significant impact on the hydro-mechanical properties of soils, yet quantifying crack patterns remains challenging. This study presents a quantitative framework with a total of 26 parameters for characterizing the geometric and morphological characteristics of soil desiccation crack patterns, including soil clod parameters (soil clod area, soil clod perimeter, number of clods, and the probability density distribution of clod parameters, etc.) and crack network parameters (crack length, crack width, crack inter angle, number of crack segments, surface crack ratio, crack density, connectivity index, etc.). To implement this quantitative framework, the Crack Image Analysis System (CIAS) was developed to automatically identify and analyse complex crack patterns through image preprocessing, clod identification, crack network identification and batch processing. CIAS was then applied to quantify the crack images of soil with different thicknesses, validating its efficacy. To comprehensively describe the geometric and morphological characteristics of crack networks, it is recommended to use the number of soil clods per unit area, surface crack ratio, crack density, and connectivity index as key parameters. These metrics effectively capture information on crack spacing, area, length, width, and connectivity. This comprehensive framework for characterizing and quantifying crack images is of great significant for geological engineering. Moreover, it holds great potential for application in other different disciplines such as geotechnical, hydraulic, mineral engineering and material even planetary science.

Soil tensile strength is a critical parameter governing the initiation and propagation of tensile cracking. This study proposes an eco-friendly approach to improve the tensile behavior and crack resistance of clayey soils. To validate the feasibility and efficacy of the proposed approach, direct tensile tests were employed to determine the tensile strength of the compacted soil with different W-OH treatment concentrations and water contents. Desiccation tests were also performed to evaluate the effectiveness of W-OH treatment in enhancing soil tensile cracking resistance. During this period, the effects of W-OH treatment concentration and water content on tensile properties, soil suction and microstructure were investigated. The tensile tests reveal that W-OH treatment has a significant impact on the tensile strength and failure mode of the soil, which not only effectively enhances the tensile strength and failure displacement, but also changes the brittle failure behavior into a more ductile quasi-brittle failure behavior. The suction measurements and mercury intrusion porosimetry (MIP) tests show that W-OH treatment can slightly reduce soil suction by affecting skeleton structure and increasing macropores. Combined with the microstructural analysis, it becomes evident that the significant improvement in soil tensile behavior through W-OH treatment is mainly attributed to the W-OH gel's ability to provide additional binding force for bridging and encapsulating the soil particles. Moreover, desiccation tests demonstrate that W-OH treatment can significantly reduce or even inhibit the formation of soil tensile cracking. With the increase of W-OH treatment concentration, the surface crack ratio and total crack length are significantly reduced. This study enhances a fundamental understanding of eco-polymer impacts on soil mechanical properties and provides valuable insight into their potential application for improving soil crack resistance. (c) 2024 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).

Jilin ball clay is commonly employed as a construction material for the cover layer of landfills. The differences in temperature between the outside and inside of landfill renders the internal structure and stability of cover layer susceptible to desiccation cracks. To examine this phenomenon, a series of wet-dry cyclic tests were conducted employing the digital image correlation technique. The investigation systematically explored various crack characteristics of Jilin ball clay, including cracking morphology, water evaporation rate, and crack development under different thicknesses and temperature conditions. The findings of the test demonstrate that elevated temperatures have a positive correlation with the acceleration of specimen evaporation rates, and augmenting the thickness of the specimen can effectively impede crack formation due to the compensatory effect of moisture migration on surface water loss. Furthermore, the maximum values of crack length are attained prior to the inflection point of the desiccation curve during each cycle, and this trend becomes more pronounced as the temperature increases. However, the regularities in the pattern of changes in the average width of cracks were comparatively weaker when influenced by variations in thickness and temperature. The impact of wet-dry cycles on cracking parameters was primarily concentrated on the initial and subsequent cycles. The test results provide reference values for the subsequent research of drying-induced crack growth in Jilin ball clay.