Interaktionen zwischen Abdichtungsbauwerk und Wirtsgestein im Steinsalz

Interaction between sealing structure and host rock in rock salt

During the development of radioactive waste disposal it is intended to prevent the inflow of water and solution over a long period of time to reach the safety objective at the surface. As the inflow cannot be completely excluded when considering a worst case scenario, the access drifts towards the emplacement chambers have to be sealed. This function is primarily influenced by the interaction between the host rock and the sealing structure. The excavation damaged zone close to the contour, contact zone, stress redistribution in the host rock and the creeping capacity of the host rock are particularly relevant for the sealing. In addition, the characteristics of the sealing structure's building materials have to be considered: the cooling phase after the setting process and autogenous shrinkage lead to the development of gaps between the sealing structure and the host rock. These gaps have to be injected in order to reach a short-term operability, while the long-term low permeability can be provided by the creeping host rock. It became clear that the portability of the model concepts based on the experiences in mining and civil engineering have to be questioned, especially with regards to possible fluid flow.