Multiyield-Surface Implementation of a Simplified Three-Dimensional Hoek–Brown Strength Criterion

Abstract

This work presents the implementation of a simplified three-dimensional Hoek–Brown strength criterion using a multiyield-surface plasticity approach. The adopted three-dimensional simplification of the strength criterion accounts for the intermediate principal stress influence, maintaining the simplicity in the numerical implementation. This criterion corresponds to a paraboloid surface of circular cross section in the principal stress space. The introduction of multiple yield surfaces allows for a smooth definition of the nonlinear stress–strain behavior of the material. In addition, a kinematic hardening rule is adopted, allowing yield surfaces to translate with loading, enabling a hysteretic and path-dependent stress–strain response.