ABSTRACT
The composite model describes the transient and steady-state creep of natural rock salt on the basis of the deformation micromechanisms (dislocation glide) and micro structure (dislocation subgrains; impurities in the salt matrix as obstacles against dislocation glide). The model uses physical quantities as fit parameters that can be checked in independent measurements, observations, and in comparisons with deformation theory. Successful checks demonstrate the validity and reliability of predictions of the long-term creep behavior of rock salt that are made with this model. Such calculations are necessary for the safety assessment of a permanent repository for hazardous wastes in salt.
In this paper, the basic ideas of the composite model and an overview about its current modified formulation, used for the application in numerical computer codes, will be presented. Also, comparisons between modeled and measured creep curves will be shown.
