A two-scale modelling of a swelling clay

A non-linear poroelastic approach is proposed to model the swelling of a satured clay which occurs when it comes into contact with a salt solution out of equilibrium with the saturating solution. The clay is considered as a porous material formed of two phases, namely the solid skeleton of which the swelling is observed and a liquid phase which has two components: the free water in the connected porosity and the salt in solution. The coefficients of the macroscopic constitutive equations account for the electric interaction between the electrolyte and the negatively charged clay particles. They are determined theoretically through a micro-macro approach involving the electric double layer theory at the microscopic level.