Numerical Studies of Foundation Behavior Subjected to Combined Loading Considering Hydrostatic and Transient Flow Conditions in Unsaturated Soils

Conventional soil mechanics are widely used for investigating shallow foundation behavior when subjected to vertical, inclined, and eccentric loading. However, few studies in the literature focus on the behavior of foundations that extend unsaturated soil mechanics for combined loading conditions that consider the influence of hydrological events. In this study, finite-element analysis (FEA) is undertaken for shallow foundations that are subjected to vertical, inclined, and eccentric loading that considers hydrostatic and transient flow conditions. The variation in the soil properties with respect to matric suction is achieved with a subroutine USDFLD that is exclusively developed for this study to undertake FEA using ABAQUS software. In addition, the soil properties’ spatial variability is considered using a random field, which is generated by the midpoint method that is based on the Cholesky decomposition technique. Comparison studies are conducted between the FEA, experimental, and analytical studies on homogenous soils that show good agreements for bearing capacity and failure envelopes. In addition, investigations are conducted on homogenous and nonhomogenous soils to understand the differences between the foundation failure envelopes and mechanisms. The comprehensive investigations provide valuable information that is based on the developed numerical framework for the reliable assessment of the service state of shallow foundations in unsaturated soils.