Comparison of the nonlinear elastic and elastoplastic models in THM response of unsaturated soils

The paper presents a comparison between the nonlinear elastic and elastoplastic models for Thermo-Hydro-Mechanical (THM) behaviour of an unsaturated medium. A fully coupled thermo-hydro-mechanical formulation for an unsaturated soil is considered using net stress, suction as two state variables. In this formulation, all significant coupled interactions between the different components involved in an unsaturated porous medium subjected to heating have been taken into account. The coupling effects of temperature, moisture content and deformation of skeleton are included in the nonlinear elastic model, via the temperature-dependent state surfaces concept. After a brief description of the formulation, the basic principles of the elastoplastic model are described, which considers a temperature-dependent yield surface with an associated flow rule. Then, the strong ability of this model is shown by presenting the results of analyzing of an applicative example using this model, and compared with the nonlinear elastic model using the code è-Stock.