ABSTRACT
Mogilno salt dome has very complicated geological structure, thus natural gas storage caverns had to be placed at various depths, in rock salt of different strength and creep properties. Creeping law parameters given by laboratory testing of core samples can be inadequate. The paper presents selected results of the sensitivity study on influence of exponent in Norton law and boundary conditions on strain and stress state of rock formation around the storage cavern and its convergence. It was found that, in several cases, lower exponent and thus lower creeping rate leads to greater strains on the cavern wall and higher cavern convergence. This behavior can be caused by greater influence of effective stress reduction than that of strain rate resulting from the creeping law. It means that caverns in rock salt of smaller creeping rate reaction on effective stress change can be less stable than in case of greater creeping.
