Liquid phase transport in heterogeneous media such as gels and biopolymers may induce very large strains. These produces internal mechanical stresses that interact with water transport mechanisms. We analyze transfers in porous media saturated with an ionic solution using the linear thermodynamics of irreversible processes. The interaction between mass transfer and stress/strain is analyzed using free energy. A large number of coefficients appears and we proposed theoretical and experimental method for their determination. A validation of the model is given in the simplified case of osmotic dehydration of Agar gel.