Numerical investigations of the failure mechanism evolution of rock-like disc specimens containing unfilled or filled flaws

The mechanical responses and ultimate failure patterns of rocks are associated with the failure mechanism evolution. In this study, smoothed particle hydrodynamics (SPH) method with the mixed-mode failure model is proposed to probe into failure mechanism evolutions for disc specimens upon loading. The tensile damage model and the Drucker-Prager model are used to calculate the tensile failure and shear failure of the material, respectively. It is concluded that for flaw-unfilled disc specimens, the crack coalescence mechanism in the rock bridge area is affected by the flaw inclination angle and the material property. Considering disc specimens with filled flaws, the incremental rate of tensile damage grows more rapidly when the disc and filling material have a closer ratio of tensile strength to cohesion, which makes the entire specimen response greater brittleness. Furthermore, with the increasing non-uniformity of filling distribution, the incremental rate of tensile-activated damage decreases and the disc specimen performs more ductile. Besides, the influence of the fillings is greater when the flaw inclination angle is approaching 45°. It is proved that the proposed SPH method can be used to simulate the failure mechanism evolution of rocks, which lays a foundation for the study of more complex rock failure.