Improvement of coupled thermo-hydro-mechanical model for saturated freezing soil

Aiming at the shortcomings of the coupled thermo-hydro-mechanical model for saturated freezing soil, which employs a simplified linear elasticity constitutive relation, the assumption of complete saturation and the energy conservation based on conduction, a model is proposed by introducing the latest achievements of frozen soil. Firstly, the viscoelastic dissipation potential constituted by the strain rate and temperature rate is introduced, and a viscoelastic constitutive model that can consider the environmental effects of temperature is established. Then based on the theory of multiphase porous media, the mass conservation equation of frozen soil is established under the combination of load and temperature. By considering the main factors of the viscoelastic dissipation potential of frozen soil such as heat-mechanical coupling dissipation potential and thermal convection caused by water migration, the energy conservation equation is established. Finally, the governing differential equation is formulated by combination of the above equations, and the accuracy of the equation is verified by a classical laboratory test. It is shown that the results of the proposed model are well adapted for practical engineering.