Multi-Physical Simulation of Freezing Unsaturated Soil

This paper introduces development of a multiphysical model to simulate the coupled hydro-thermo-mechanical field for unsaturated porous materials. The coupling integrates the Fourier's laws for heat transfer, Richard's equation for fluid transfer, and a linear constitutive relationship. Numerical simulations were implemented by a FEM platform to solve the coupled nonlinear partial differential equations. A simulation case was carried out on a relatively simple geometry, using an accepted model for thermal, hydraulic and mechanical properties. Results of multiphysical simulations, (such as the freezing induced moisture redistribution, the thermal stresses, etc) are consistent with the basic laws and experience. A unique feature of this model is the coupling of the stress field in addition to the thermo-hydraulic process. The model is under further refinement to study freezing-induced stresses in porous materials.