Salt-mudstones and rock-salt suitabilities for radioactive-waste storage systems: rheological properties

Rheological properties of salt massif are crucial factors deciding about its tightness. The purpose of this article is the comparison of stationary creep rate of salt-mudstones with salt rock. The object of the research was brown and red salt-mudstone containing 20–30% of insoluble parts. It was found that the content of insoluble parts has no significant rheological influence. On the basis of the calculated coefficients for the Norton creep law, we may state that salt-mudstoneʹs creep rate strongly depends on the temperature and on the effective stress in the same manner as for rock salt. The boundary values of relaxation also depend on temperature. Salt-mudstone with a considerable content of rock salt is a medium suitable for the construction of a radioactive waste repository.