Application of a Coupled Thermo-Hydro-Mechanical Model to Simulate the Drying of Nonsaturated Porous Media

This study deals with drying modeling of a partially saturated deformable porous media (solid, liquid, and gas phases). In fact, during their drying, the deformable porous media undergo stresses due to volume shrinkage. The objectives of the model are to foresee the mechanical stresses in order to control the deformations of the product. Modeling of drying has been worked out for saturated media as well as for unsaturated media. The problem deals with the level of the transition between saturated and unsaturated medium where a continuous physical modeling does not exist currently. In this work, a mathematical model is proposed to describe the heat, mass, and momentum transfers applied to the drying of an unsaturated and deformable medium. The pressure gradient is the main driving force for the water migration through Darcy's law. The particularity of the model is that it takes into account the strong coupling between mass transport and mechanical behavior of the material while using the notion of effective stress. The variables of coupling are the solid deformation velocity and the liquid phase pressure. The model is validated for clay material in various convective drying conditions. The simulations show the feasibility of the model to describe the drying and the deformation of a partially saturated media.