Rheology of rock-salt and its application for radioactive waste disposal purposes

The principle features of the rheological processes in rock salt are plasticity, creep and fracturing. A treatment of these features involves geotechnical measurements (laboratory, in-situ), theoretical investigations (continuum mechanics), and microphysical considerations (dislocations, grain structure). The knowledge of the thermo-mechanical behavior of rock salt is an essential part of any assessment of the stability of underground openings for waste disposal purposes. Each, an assessment and the evaluation of the integrity of the geological barrier can only be performed by calculations with validated geomechanical models. Some results of these calculations for the preliminary repository design of the Gorleben site and the research mine ASSE II are given