Influence of dissolution on the mechanical behaviour of saturated deep argillaceous rocks

In this paper, the influence of a dissolution on the hydro-mechanical behaviour of a deep argillaceous rock, called Bure argillite, is investigated. As dissolution increases the porosity, it has a direct impact on the hydric behaviour of the rock. A corresponding model is proposed, with a new definition of the internal energy balance. The model enables the description of chemical reactions in an unsaturated porous medium. The kinetics of the dissolution is taken into account in the model. Constitutive equations are detailed. The model is implemented in Castem 2000, the French Nuclear Agency (Commissariat à lʹEnergie Atomique) finite elements code. A benchmark is done to improve the knowledge about the coupling coefficient between dissolution and porosity.