Anisotropic hydro-viscoplastic modelling of a drift at the Meuse/Haute-Marne URL.

The Meuse/Haute-Marne underground research laboratory was built in the Callovo–Oxfordian (COx) clay formation for the purpose of assessing the feasibility and safety of a deep geological formation to host an industrial radioactive waste repository (Cigéo project) in France. Some observations related to the drifts oriented in the direction of the major horizontal stress remain to be theoretically and numerically understood. In order to contribute to the understanding of the hydromechanical behaviour of the COx claystone, an elasto-viscoplastic model with transient creep was developed, including the inherent elastic and hydraulic anisotropies. Comparison with in situ measurements was made, with encouraging results. [ABSTRACT FROM AUTHOR]