Experimental characterization of the thermo-poro-mechanical properties of the Aegion Fault gouge

The experimental characterization of the thermo-poro-mechanical behaviour of Aegion Fault drilling cores is presented. The heart of the fault is met at a depth of 760 m and consists of clay-rich material on a length of about I m. This zone is surrounded by a cataclastic one. Here the thermo-poro-mechanical behaviour of the clayey core is investigated by means of oedometer and triaxial compression experiments. It is shown that softening behaviour under thermal loading is possible. Thermal collapse of the material may thus activate fluid pressurisation inside the fault and trigger fault slip. In addition, the behaviour of the interface between the intact rock and the cataclastic zone is studied by direct shear tests. To cite this article: J. Sulem et al., C R. Geoscience 336 (2004). (C) 2004 Academie des sciences. Published by Elsevier SAS. All rights reserved.