Numerical investigation of rock heterogeneity effect on rock dynamic strength and failure process using cohesive fracture model

In this study, a cohesive fracture model (CFM), which assumes rock material as assemblage of deformable grains joining together at their cohesive boundaries, is developed to simulate rock fracture and failure behavior in terms of mineral and cement properties. To better represent the structural bonds between the particles and the heterogeneity of rock material, a user-defined material model (UMAT) for the cohesive element with stochastic strengths is incorporated into the developed CFM. The capability of the developed model for rock fracture problems under both static and dynamic loads is first explored. Based on the developed model, the heterogeneity effect of rock on its dynamic failure process and dynamic strength is then studied. The results demonstrate that the developed CFM can be used to investigate the rock fracture problems under both static and dynamic loads. The heterogeneity of rock material not only affects the rock dynamic failure process but also leads to an increase of rock dynamic strength.