Determination of mobilized strength properties of degrading sandstone

This paper describes a method for calibrating elasto-plastic models based on the results of triaxial tests on two types of sandstones. Emphasis is given to the simulation of the softening regime of the stress–strain response of the material with special attention to minimizing mesh-dependency. A pragmatic and easy-to-implement procedure is developed for the calibration under the framework of friction hardening/cohesion softening. Fracture energy regularization is applied in the back-analysis of the triaxial tests to remove mesh dependency. The impact of different mesh designs is investigated. Oriented mesh with the same inclination as the shear band provides the most realistic outcome and is able of capturing real shear band thickness.