“EFFECT OF TEMPERATURE AND SATURATION ON THE MECHANICAL BEHAVIOR OF CALLOVO-OXFORDIAN CLAYSTONE”

As part of the optimization of the underground structures of the Cigéo repository project, the potential future gains will result from a better representation of the diffuse damage of the Callovo-Oxfordian argillite and from a more detailed characterization of the associated thermo-hydro-mechanical parameters. Previous studies have shown a greater influence of relative humidity on compressive strength than temperature. In addition, the characterization tests carried out on samples having been exposed to very high temperatures during the CRQ and ALC1605 experiments carried out in situ within the Meuse/HauteMarne underground research laboratory indicate little or no alteration of the mechanical properties. Moreover, compression tests on heated samples carried out as part of the HITEC Work Package of the European EURAD program indicate a slight drop in resistance with temperature. In order to increase the understanding of the influence of the saturation state on the behavior of the tested samples, the thesis work will focus on the study of the impact of temperature on the hydromechanical behavior of the Callovo-Oxfordian argillite.
The GeoRessources laboratory, and more particularly the HGM (Multi-Scale HydroGeoMechanics) team, has been involved for many years in laboratory experiments aimed at characterizing the mechanical behavior of Callovo-Oxfordian argillite and the impact of temperature, within the framework of collaborations with ANDRA and within the framework of the European EURAD project. The proposed thesis is a continuation of these previous works. She is motivated by the need to perform a large amount of innovative laboratory experiments.

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