A Fully-coupled Thermo-Hydro-Mechanical Model for the Description of the Behavior of Swelling Porous Media

Although many numerical models have been proposed for unsaturated porous media, unrealistic assumptions have been made, such as the non-deformable nature of media, constant material properties, the neglecting of convection heat flow transfer, and static air phase. Most of these conditions are not justifiable for porous media with low hydraulic permeability and high swelling activity. In the present article, a fully coupled thermo-hydro-mechanical model is proposed that takes into account nonlinear behavior, including both the effects of temperature on dynamic viscosity of liquid water and air phase, and the influence of temperature gradient on liquid and air flows. Fully coupled, nonlinear partial differential equations are established and then solved by using a Galerkin weighted residual approach in space domain and an implicit integrating scheme in time domain. The obtained model is finally validated by means of some case tests for the prediction of the thermo-hydro-mechanical behaviour of unsaturated swelling soils.