Modeling of hydro-mechanical behavior of rock salt in the near field of repository excavations

Abstract

In this paper, the development of the Excavation Disturbed Zone (EDZ) in the rock salt around a disposal drift and the consolidation behaviour of backfill material are presented. In order to perform this analysis, finite element codes containing a set of time- and temperature-dependent constitutive models have been used. A new viscoplastic constitutive model for rock salt that can describe the damage of the rock is proposed. The results of the simulations show that under expected repository conditions the volume closure and the compaction of the backfill are mainly determined by the temperature increase and the lithostatic pressure. Furthermore, the numerical results demonstrate the importance of the increasing compaction pressure in the backfill on the evolution of the EDZ.