ABSTRACT
The dilatancy concept provides the criterion to decide whether creep deformation without volume increase or dilatant deformation with propagating damage will occur. Different observation methods are commonly used to detect dilatancy related effects. Since the different effects seem to suggest different dilatancy boundaries, the equations for the dilatancy boundary can be very different. We present our recent results and a comment on the various methods to detect dilatancy. The evolution of damage is discussed on the basis of the volumetric strain, and the energy to produce the irreversible volumetric strain yields a measure for the occurrence of failure. First results from our laboratory work on the compaction behavior of heavily damaged rock salt like that one in the EDZ are presented. Based on these results, the compaction and permanent healing are described by the evolution of the permeability during a transition from the dilatant into the non-dilatant stress domain.
