ABSTRACT
Damage reduction (healing) of rock salt is one of four laboratory research topics in joint project WEIMOS. Damage reduction is important for long-term safety of nuclear waste repositories in rock salt because it is directly linked to the time span needed for geotechnical barriers and the surrounding rock salt to reach long-term hydraulic tightness. In the WEIMOS damage reduction laboratory tests, which have been performed by TUC, samples of natural salt have first been damaged to specific values of dilatancy. Afterwards, the reduction of dilatancy at different temperatures and stress conditions has been observed over several months using high-precision measurement devices. Overall, four damage reduction test series with 34 damage reduction tests on Asse-salt and 10 damage reduction tests on WIPP-Salt in total have been performed within the WEIMOS project. Based on the test results, each project partner improved the damage reduction formulation within their constitutive models. These improved models were then used to simulate the damage-evolution around an emplacement drift, with increasing damage during the open drift phase and decreasing damage after including a sealing dam construction within the emplacement drift. This paper will present exemplary lab test results as well as selected simulation results.
