Numerical Simulation of Desiccation Cracking in Clayey Soil Using a Multifield Coupling Discrete-Element Model

Abstract

Desiccation cracking in clayey soil, which may lead to soil erosion, geotechnical engineering accidents, or even environmental pollution, is a serious problem nowadays. This research proposed a multifield coupling discrete-element model of clayey soil, in which each element represented a certain volume of soil. Meanwhile, the uneven distribution and transfer of moisture were also achieved. By establishing the relationships between water content and element radius, Young’s modulus, and tensile strength, respectively, the model coupled the moisture field with the stress field. Through a discrete-element simulation of desiccation cracking in a thin clay layer, the gradual development of crack network was successfully reproduced, and the proposed model was validated. The uneven moisture distribution in the numerical specimen indicates that cracks can intensify evaporation by increasing the area of soil-air interface. Layer thickness, evaporation intensity, soil-base interaction, and compressive strength are proved to have significant impacts on crack pattern by influencing the equilibrium between desiccation shrinking and cracking. This research provides a new means to study the mechanism of desiccation cracking under multifield coupling effects.