Solid-Fluid Segregation in Saturated Porous Media

In this paper we study a model to discuss phase transitions in consolidation processes typical of soils. The problem is faced in the context of the Biot theory for saturated porous media. We show that by adding higher order terms to the standard Biot energy, depending on the solid deformation and on the mass fluid content measured w.r.t. a reference fluid configuration, it is possible to predict the existence of two stationary states. One of the states is much similar to the usual state described by the Biot theory, the second state is reacher in fluid and mimics the behavior of pore-fluid segregated porous media. We discuss the predicted behaviors in terms of the Biot constitutive coefficients.