Saturated elastic porous solids: Incompressible, compressible and hybrid binary models

Constitutive models for a general binary elastic-porous media are investiga ted by two complementary approaches. These models include both constituents treated as compressible/ incompressible, a compressible solid phase with a n incompressible fluid phase (hybrid model of first type), and an incompres sible solid phase with a compressible fluid phase (hybrid model of second t ype). The macroscopic continuum mechanical approach uses evaluation of entr opy inequality with the saturation condition always considered as a constra int. This constraint leads to an interface pressure acting in both constitu ents. Two constitutive equations for the interface pressure, one for each p hase, are identified, thus closing the set of field equations. The micromec hanical approach shows that the results of Didwania and de Boer can be easi ly extended to general binary porous media.