Thermo-Hydro-Mechanical Analysis of Soil-Pile Interaction in Expansive Unsaturated Clays during Natural Evaporation and Infiltration

The swelling of expansive soils in the active zone can impose intolerable uplift forces on piles' skin. Therefore, it is critical to accurately estimate the wetting-induced swelling and drying-induced shrinkage of expansive soils and soil-pile interactions to help minimize damage to the buildings. In this study, a coupled thermo-hydro-mechanical (THM) model is utilized to estimate the active zone, swelling deformation of the soil, and the soil-pile interactions, when the soil is subjected to real-time meteorological data. The THM model and the input thermal, hydraulic, and mechanical data are implemented in COMSOL Multiphysics. The comparison of the simulated swelling/shrinkage deformation with the analytical calculation produced by VOLFLO software showed a reasonable outcome of the numerical model. The coupled THM modeling approach presented in this paper employs a few input parameters that can be measured using conventional methods and can be incorporated in the rational design of pile foundations in expansive soils.