Simulation of Viscoplastic Material Behavior in Numerical Models

Granular rock salt as a strong time dependent and stress dependent material behavior. For the numerical simulation of this material behavior a new viscoplastic constitutive law was developed and implemented into a Finite-Element-(FE-)Program. The numerical simulation of the material behavior is necessary for the analysis of the stability and the serviceability of large tailings heaps and infrastructure construction in the area around these heaps. The tailings heaps occur during the production of potassium fertilizer and consist of granular rock salt. The paper explains the mathematical formulation of the new viscoplastic constitutive law which is called ViscoSalt 2017 and the implementation into a FE-Program. The salt mechanical material parameters for this constitutive law are determined by load controlled triaxial creep tests and strain rate controlled triaxial fracture tests. For the verification of the new constitutive law and the correct implementation into the FE-Program the back analysis of the triaxial tests is used. Now the new constitutive law is used for the analysis of the stability and the serviceability in engineering practice.