GURTIN-TYPE VARIATIONAL PRINCIPLES FOR DYNAMICS OF A NON-LOCAL THERMAL EQUILIBRIUM SATURATED POROUS MEDIUM

Based on the porous media theory and by taking into account the effects of the pore fluid viscidity, energy exchanges due to the additional thermal conduction and convection between solid and fluid phases, a mathematical model for the dynamic-thermo-hydro-mechanical coupling of a non-local thermal equilibrium fluid-saturated porous medium, in which the two constituents are assumed to be incompressible and immiscible, is established under the assumption of small deformation of the solid phase, small velocity of the fluid phase and small temperature changes of the two constituents. The mathematical model of a local thermal equilibrium fluid-saturated porous medium can be obtained directly from the above one. Several Gurtin-type variational principles,especially Hu-Washizu type variational principles, for the initial boundary value problems of dynamic and quasi-static responses are presented. It should be pointed out that these variational principles can be degenerated easily into the case of isothermal incompressible fluid-saturated elastic porous media, which have been discussed previously.