Hydro-mechanical response of Opalinus Clay shale: dependency on composition and burial depth

Shales are sedimentary formation currently studied for their involvement in many geo-energy related applications, such as radioactive waste disposal, CO2 sequestration, oil and gas extraction. In Switzerland the Opalinus Clay shale has been selected has host formation for the construction of geological disposal for radioactive waste. Opalinus Clay is a Jurassic shale widespread in the northern part of the country, characterised by sedimentation planes (bedding). In the shale formation, several lithostratigraphic units have been identified. Also, the current and maximum depths that the formation has experienced are not homogeneous among the locations. Most of the research in the last 20 years have been concentrated on one of the lithofacies (characterised by high clay content), the shaly facies, in the rather shallow location of the Mont Terri Underground Rock Laboratory, and on a few other deeper sites, in the north-east of the country. This thesis aims to study the impact of the composition and burial depth on the hydro-mechanical response of the Opalinus Clay. The results serve to estimate the geomaterial response for compositions and locations (e.g., where the disposals are planned) where the possibility to directly test the shale may be limited because of cost and time efforts. An experimental study was carried out, to test the hydro-mechanical response, in saturated and unsaturated conditions, of samples from various locations and compositions. Samples from sub-superficial locations (