Multi-physical modeling of climate-driven elasto-plastic deformation, stress redistribution, and water potential in desiccation-cracked soils of arid regions

This study presents a multi-physical modeling approach to analyze the dynamics of moisture potential and stress-deformation features near deep desiccation cracks in clayey soils under three consecutive years’ climate variability in an arid region. A triple research approach of statistical analysis, analytical framework, and numerical modeling was used to investigate the complex thermo-hydro-mechanical behavior of desiccation-cracked soil, incorporating realistic climatic data of Qom, Iran. The results revealed the interplay between stress, strain, and pore water pressure over time, demonstrating that soil experiences significant swelling and shrinkage due to cyclic wetting and drying. The horizontal stress distribution shows compressive stress concentration at crack tips during wetting, transitioning to tensile stresses uniformly across the soil surface during drying paths. Similarly, vertical stress distributions exhibit localized compressive stresses along crack boundaries during wetting and tensile stresses during drying, highlighting the critical stress conditions at crack tips. The model differentiates between microstructural and macrostructural changes in porosity. Annual trends in micro-porosity revealed cyclic-dependent behavior, with significant volumetric changes occurring in the first year, stabilizing with successive cycles. The results also indicated that part of the volumetric changes are irreversible, with volumetric plastic strain increasing exponentially but at a decreasing rate over three years. Principal stress analysis indicates a shift from compressive to tensile stress states around cracks, driven by climate-induced wetting and drying cycles. These findings underscore the critical role of climate variability in shaping cracked soil behavior in arid regions, providing insights into the heterogeneous behavior of cracked soil surficial layers.