Existing Methods for Swelling Tests – A Critical Review

Argillaceous and anhydritic rocks as well as rocks containing pyrite are prone to swelling, i.e. to adsorb water, which either increases their volume or, in the case of deformation constriction, causes an external pressure. Until now, the only adequate way to quantify the swelling potential of rocks is via swelling tests on undisturbed rock samples. The testing technique has been developed since the 1970's. The recommendations published in Germany, Switzerland and by the ISRM are reviewed. Furthermore the most important aspects concerning the testing techniques of swelling rocks are discussed which need to be modified for future testing.