Modelling of dynamic tensile failure of inclusion-bearing rocks

Abstract

Natural and synthetic inclusions may modify the tensile strength and the failure pattern of surrounding rocks. Understanding the failure mechanism could improve rock failure prediction and induced geohazard mitigation. Due to difficulties in controlling the geometrical and mechanical properties of embedded inclusions in the laboratory, we simulate the dynamic tensile failure of inclusion-bearing rock specimens using a two-dimensional particle flow code model. We investigate the effects of strength ratio, loading rate, and treatment temperature on the nominal tensile strength of inclusion-bearing specimens and discuss the brittleness index to interpret the strength evolution. We identify the dominant effect on the nominal tensile strength as strength ratio for a low tensile strength inclusion and loading rate and treatment temperature for a high tensile strength inclusion. The change in dominant effect is associated with induced cracks primarily formed in the rock/inclusion part with lower tensile strength and highlights key factors to control inclusion-induced rock failure. This study also reveals that low strength, large size inclusions promote a decrease in brittleness index and accelerate the degradation of inclusion-bearing rocks.