Finite discrete element modeling of desiccation fracturing in partially saturated porous medium

In this study, a numerical framework is presented for the analysis of desiccation fracturing in variably saturated porous media. The solid phase deformation and fracturing are obtained based on the 2D finite-discrete element method (FDEM), while the fluid flow is characterized by nonlinear Richards' equation and solved by finite volume discretization. The coupling between phases is realized by Biot's porous media theory. The capabilities of the model in capturing the unsaturated porous medium flow and coupled hydro-mechanical effects are put to the test against benchmark solutions available in the literature. Furthermore, mechanisms of desiccation cracking in the soil are thoroughly investigated through various numerical test cases. In line with experimental observations, results indicate that the type of mechanical constraints and saturation gradients are two main factors contributing to the generation of cracks in desiccation processes.