Skeletal thermal expansion coefficient and thermo-hydro-mechanical constitutive relations for saturated homogeneous porous media

A rigorous treatment of the thermal expansion coefficient of the solid skeleton for saturated homogeneous porous media is presented. It is shown that the overall thermal expansion coefficient of a porous medium is equal to the thermal expansion coefficient of the solid constituent. It is also shown that the size of the pores and porosity has no influence on the thermal expansion coefficient of a porous medium, and the void ratio is independent of the thermal expansion of the solid skeleton in the elastic region of the material response. In addition, non-isothermal constitutive relations for saturated porous media are presented, and a closed form solution for the heating-induced pore pressure is derived. The validity of the theoretical assertions is examined through a targeted program of laboratory testing as well as data from the literature.