Viscoelastic-Viscoplastic Formulas for Analysis of Cavities in Rock Salt
The material model consists of a viscoelastic Burgers element and an additional viscoplastic element, which includes Bingham viscosity and a viscoplastic Kelvin element. For spherical and cylindrical cavities, expressions are derived for the stress and strain fields and volume convergence. Spherical and cylindrical cavities are treated in a unified formulation. The expressions for the transient ph