ABSTRACT
A new phenomenological model for the description of healing of damage and dilatancy in rock salt has been implemented in the Hou/Lux constitutive model ( Hou, Lux, 1998 ). It was tested in laboratory tests and applied to an in-situ project in rock salt. Based on the laboratory results, three phases to describe decrease of damage and dilatancy could be identified. A change in the applied load, i.e. a decrease of deviatoric stress and simultaneous increase of isotropic stress, creates a stress state that provides good healing conditions, so that in the first phase of the healing process (micro-)cracks are degenerated and closed to a large extend. This first phase is called the fissure closing phase. In the following second phase, which is called fissure sealing phase, cracks are closed as well, but not as fast as in the fissure closing phase as it is time-dependent contrary to the load-dependent fissure closing phase. When both, the fissure closing phase and the fissure sealing phase are concluded, the third and actual healing phase begins. It is assumed that in this phase, the mineral structure of nearly closed cracks in the rock texture and thus its mechanical properties are restored by rearranging grain boundaries, forming sub-grain structures and new grains via mass transport effects. The new healing model was validated by means of numerical simulations of a lab test, one in-situ situation, and of one hypothetical situation.
