Structural Modifications of a Hard Deep Clayey Rock due to Hygro-Mechanical Solicitations

Abstract

Wetting/drying tests including cycling effects were performed on an argillaceous deep rock coming from a Callovo–Oxfordian deposit in eastern France. Bulk volume and water content were measured in order to estimate the importance of physical changes. Then, mercury intrusion porosimetry (MIP) was performed on dry and moist samples in order to quantify the influence of hydraulic history on fracture. Results showed that shrinkage and swelling caused microcracks, which led to volume variations thus altering the structures of the rock. MIP tests performed on moist samples equilibrated with different hygrometric saline solutions allow unsaturated pores and classic water retention curves to be described so as to explain changes in the microstructure.