Thermo-mechanical-water migration coupled plastic constitutive model of rock subjected to freeze-thaw

Abstract

A general thermo-mechanical-water migration coupled constitutive model was proposed to model mechanical degradation of rocks subjected to freeze-thaw cycles. This model is proposed in generalized incremental form under the framework of thermodynamics based on internal state variables theory. Migration of unfrozen water during freezing was considered to match the actual situation in practice. The model can adapt to a variety of inelastic deformation dissipation mechanisms. Therefore, it applies to many kinds of rocks. In the paper, a specific example was presented to demonstrate the application of the general model. In the example, two typical dissipation mechanisms, damage and isotropic hardening are chosen. After degradation of the general model, a practical model is obtained. In the practical model, effect of freeze-thaw on initial damage, damage threshold and isotropic hardening ability were modeled. For verification, an application based on real experimental data was presented. Application results show that this model can well simulate the mechanical response of rock after freeze-thaw cycles.