Time-Dependent Behaviour of Underground Openings in Rock Salt

In rock engineering, the creep behaviour is critical for the structure's long-term stability and failure prediction. The creep is an important mechanism to consider when designing projects with extremely long lifespans, such as nuclear waste repositories. Therefore, in the present study, numerical investigations are carried out for the rock masses which exhibit creep. The creep behaviour of rocks is investigated by considering the viscoelastic constitutive law in the finite element-based numerical tool. The cylindrical-shaped cavern in rock salt is investigated in this study concerning overburden depth, aspect ratio, and time. The results obtained from the investigations show inward displacement at the cavern crown and cavern wall. The uplift displacement of the heel is also observed in the analysis. The study showed that the increase in cavern's aspect ratio and overburden depth increases the cavern's wall, crown, and bottom displacement, which results in the reduction of the cavern dimensions with time. The findings suggest that unlined cavern displacement may be accurately predicted by using a power-law creep model.