Influence of Temperature and Deviatoric Stress on Creep Behavior of Rock Salt

Abstract

Rock salt deposits are used as depositories for hazardous wastes and oil due to their excellent mechanical properties for depositories such as low permeability and self-healing. The creep behavior of rock salt plays a major role in the long-term stability of rock salt depositories. Temperature and deviatoric stress significantly impact the creep behavior of rock salt. This paper studies the influences of temperature and deviatoric stress on the creep behavior of natural single-crystal rock salt specimens using creep experiments. A special triaxial thermal cell was developed to conduct the experiments. Prismatic specimens were cut out of a large mass of a sample that was acquired from Windsor Salt Mine, Ontario, Canada. The prepared specimens were tested in one-dimensional creep experiments at 20, 100, and 150° C temperatures and under 1 MPa confining pressure. Constant deviatoric stresses (σd ) of 4, 10, and 12 MPa were applied to the specimens. Increasing the applied deviatoric stress and temperature caused an increase in the accumulated strain during the experiments and resulted in higher steady-state strain rates. Although the transient strain rate is increased at elevated temperatures, it appears to be insensitive to the applied deviatoric stress.