Finite element modeling of thermo-hydro-mechanical coupled processes in clay soils considering bound water dehydration.

This paper presents a new finite element method (FEM) model to simulate the thermo-hydro-mechanical (THM) responses of water-saturated clay soils. The model can account for the effects of temperature variation on bound water dehydration and the corresponding thermo-poromechanical strains. The governing equations, including mass balance, momentum balance, and energy balance, are derived based on the principles of continuum mechanics for porous media. The impact of bound water dehydration on THM behavior is incorporated into the coupled THM equations. The model is equipped with an unconventional plasticity for more accurate description of elastoplastic behavior. To solve the nonlinear system of equations, a modified Newton–Raphson method is employed. The model is validated using laboratory tests on various clay soils with different geological origins, and reasonable agreement is achieved. The thermally induced contraction behavior of clay soils at a low overconsolidation ratio and thermally induced expansion behavior at a high overconsolidation ratio are well simulated. During heating, the effect of bound water dehydration on the generation of excess pore pressure in clay soils is highlighted in our numerical results. [ABSTRACT FROM AUTHOR]