Mechanical behaviour of a jointed rock mass with a circular hole under compression-shear loading: Experimental and numerical studies

Abstract The tunnels excavated in a mountain body interact with the jointed rock mass under compression-shear and present a complex stress state. The joints often have a significant influence on the possible damage points of tunnels. However, the failure behaviour of jointed rock mass with a hole under the compression-shear condition is still unclear. The crack coalescence mechanism needs to be further explored. In this study, compression-shear tests were carried out on jointed rock-like specimens containing a circular hole. The corresponding numerical model was established by the discrete element method (DEM) modelling. The results show that with the increase in joint inclination, the peak load first increases and decreases. Four types of crack coalescence among joints and three kinds between joint and hole were found. The crack coalesces with the hole easily occur on both sides of the hole. When the joint inclination is small, the crack coalesces through the shear slip. However, the tensile crack coalesces with the joints and hole when the joint inclination is large. Finally, the failure behaviour of the specimen was further analysed based on the displacement field. The experimental results also verify the above analysis and agree well with simulation results.