Sophie De Kock PhD

Experimental investigation of the hydro-mechanical behaviour of Boom Clay at various depths – Transfer of the knowledge gained at the level of HADES URL

For over 40 years, Belgium has been studying the possibility of a geological disposal in Boom Clay, a poorly indurated clay, as a solution for the long-term management of high-level radioactive waste and low- and intermediate-level waste, long-lived waste.

Up to now, most of the knowledge on the behavior of Boom Clay is essentially gained at a depth of 225 m in Mol, where the Belgium underground research laboratory (URL) HADES is located. Only a few tests were carried out at other depths or locations. As greater depths are being considered for a potential geological disposal facility in poorly indurated clays in Belgium, it is of paramount importance to transfer this knowledge gained at HADES URL level to greater depths and/or other locations.

The objective of this research is to study the hydro-mechanical behavior of Boom Clay from cores taken at other depths than the depth of the HADES URL and compare the obtained results as a function of the depth. Specially, cores from about 300-400 m depth, obtained from a recent non-destructive drilling, will be investigated. Additionally, specimen collected at the outcrops and at the depth of the HADES URL will also be tested in order to deduce a trend on the effect of the depth on the hydro-mechanical behavior of Boom Clay. The experimental results obtained during this project will complement the existing knowledge and will be connected with a project carried out simultaneously in the Netherlands (SECUUR project for which the objective is to characterize the mechanical behaviour and multiphysical coupling of deep poorly indurated clays). The outcomes of the project will allow to evaluate the transferability of the data gained at the HADES URL level (225 m) towards greater depths and so, will contribute to assess the feasibility and the long-term performances of geological disposal facilities, in the perspective of being constructed in the Boom Clay formation at around 400 m in depth.