Up to now salt rock mass has been predominantly regarded as a continuum and the mechanical effect of the present discontinuities and bedding planes have been neglected to a great extent. However, for a complete understanding of a couple of geomechanical phenomena this approach proves to be insufficient. When solving numerous practical problems in potash and rock salt mining it clearly turned out that a treatment without taking the existing bedding planes and discontinuities into account will not provide a satisfying explanation of the observed rock mechanical processes. Therefore, for a mechanical description of the complex properties of the salt rock mass a visco-elasto-plastic constitutive model is presented, which comprises the hardening/softening behavior and dilatancy effects for salt rocks, as well as a specific friction model, which comprises displacement-and velocity-dependent shear strength softening for salt bearing bedding planes.