In-situ measurements and 3-D model calculations of backfill compaction and EDZ development in waste disposal drifts in salt rock

摘要

To improve methods and tools for the prediction of the long-term thermomechanical behaviour of a repository for radioactive waste in salt, experimental and theoretical studies were performed in the framework of two R&D projects at the Asse mine regarding the behaviour of disposal drifts, backfill material and host rock Experimental studies included the long-term measurement of thermally induced stress change as well as permeability tests in the host rock and the excavation damaged zone (EDZ) around the test drifts. Theoretical investigation comprised the 3-D modelling of the in-situ experiment using the JIFE finite-element code. Results of calculations show that dilatancy and porosity occur in the near vicinity of the emplacement drifts. Calculated permeability increases in the vicinity of the test drifts and decreases to negligible values within a short distance. The experimental data are compared to the results of model calculations.