Clay formations in their natural state exhibit very favourable conditions for the repository of radioactive waste. In France, the Callovo-Oxfordian claystone has been studied by Andra as a possible host rock for radioactive waste disposal since the 1990's. In 2004, Andra began the construction of an underground research laboratory (called the MHM URL) in Bure, starting with shaft sinking operations (to a depth of 500 m). One of the shaft lining and surrounding rock was instrumented. Its concrete lining is highly monitored to understand its long-term behavior and the evolution of the loading due to the surrounding rock mass. Instrumentations were installed at -455 m, -467 m, -479 m, and -504 m depth. This paper presents the data collected over 18 years of monitoring. The outcome feedback consolidates the robustness of the shafts design forecast for the French Industrial Centre for Geological Disposal (Cigéo project).
The French National Radioactive Waste Management Agency (Andra) has performed in-situ experiments in the Meuse/Haute-Marne Underground Research Laboratory (MHM URL) in the context of radioactive waste disposal for two decades. The MHM URL is located in the Callovo-Oxfordian claystone (COx) formation of the eastern Paris basin at 490 m deep. The experiments performed within the MHM URL help to demonstrate the feasibility of a reversible deep geological disposal of radioactive waste (Cigéo project).
Starting in 2006, the research program became more dedicated to technological adaptations and improvements and the (multiscale) demonstration of the different issues present in the various underground disposal components (drifts, seals, disposal cells and vaults), in a way to answer the "technological readiness level" (TRL) scale, and to confirm the robustness of the proposed concepts (Armand et al. 2013).
The Cigéo project is divided into several components, in which vertical shafts helps allows the transport of machines and materials for the construction from the surface to the underground. Two shafts were built in the MHM URL, in which a shaft has been instrumented in its lining and surrounding rock to follow its behavior versus time. This information is of importance for the optimization of the shaft component in Cigéo project. This study aims to present the continuous 18 years mechanical loading feedback of the shaft final lining as well as a temperature analysis (for a better understanding of the mechanical behavior).
