Analysis of the creep and dilatant behavior of a salt cavern in long-term using Brazilian geotechnical properties

The geomechanical behavior of a salt rock cavern was studied using Brazilian geotechnical properties. To design the finite element model, it was necessary to implement, using Fortran language, a constitutive model representing the creep behavior, since the model used is not native to the program. The constitutive model implemented was the Multiple Deformation Mechanism Model. This model was chosen for being a robust model that represents the primary and secondary phases of creep and presents good agreement with the Brazilian salt rocks. The analyzes considered a period of 50 years after the mine closure and five internal pressures acting in the analyzed cave. The pressures considered correspond to 40%, 50%, 60%, 70% and 80% of the vertical stress at the top of the mine. The creep and dilation behaviors were analyzed, and the creep deformations obtained in the simulations was acceptable in relation to the failure criterion adopted in this paper. However, only the design of experiment that considered the two biggest internal pressure resulted in a permissible micro-crack ratio value.