Application and Research on the Model of Saturated-Unsaturated Porous Material Coupling Hydro-Thermal-Mechanical Process

The study of hydro-thermal-mechanical process coupling in unsaturated porous material is very important due to its close relationship with environmental geomechanics engineering. The model established upon the deforming porous material mechanics is analyzed in this study. This model takes into consideration the phase change and heat effects. Four balance equations associated with four state variables including gas pressure, capillary pressure, temperature and displacement are imposed. Besides, the governing equations are discretized with the selected Galerkin method and the program has been developed. Using this program simulates two experiments, which representing the saturated non-isothermal consolidation phenomenon and rainfall experiment respectively. The results revealed that this multi-field coupled model is a useful tool to analyze the porous material that coupled with hydro-thermal-mechanical process.

Thermal conductivity of unsaturated clay-rocks

The parameters used to describe the electrical conductivity of a porous material can be used to describe also its thermal conductivity. A new relationship is developed to connect the thermal conductivity of an unsaturated porous material to the thermal conductivity of the different phases of the composite, and two electrical parameters called the first and second Archie's exponents. A good agreement is obtained between the new model and thermal conductivity measurements performed using packs of glass beads and core samples of the Callovo-Oxfordian clay-rocks at different saturations of the water phase. We showed that the three model parameters optimised to fit the new model against experimental data (namely the thermal conductivity of the solid phase and the two Archie's exponents) are consistent with independent estimates. We also observed that the anisotropy of the effective thermal conductivity of the Callovo-Oxfordian clay-rock was mainly due to the anisotropy of the thermal conductivity of the solid phase.