Kriging-based reliability analysis of the long-term stability of a deep drift constructed in the Callovo-Oxfordian claystone

Callovo-Oxfordian (COx) claystone has been considered as a potential host rock for geological radioactive waste disposal in France (Cigéo project). During the exploitation phase (100 years), the stability of drifts (e.g. galleries/alveoli) within the disposal is assured by the liner, which includes two layers: concrete arch segment and compressible material. The latter exhibits a significant deformation capacity (about 50%) under low stress (