Macro-micro study on shear failure mechanism of rock joint based on zero-thickness cohesive element

In order to explore their shear process and failure types with different roughnesses, the ABAQUS finite element analysis software is used to simulate the shearing process of jointed rock masses under constant normal load by using the method of globally embedded zero-thickness cohesion elements. The correctness of the numerical model is confirmed by comparing the results of laboratory shear tests and numerical simulations, and the shear failure behavior of the jointed rock masses is analyzed from the macro-micro perspective. The results show that the method of global embedded zero-thickness cohesive elements to simulate the shear process of jointed rock masses is accurate and can truly reflect the microscopic process of rock joint failure. The shear peak strength of joint samples with different roughnesses increases with the roughness under constant normal load. The shear process of jointed rock masses can be divided into four stages: linearly elastic strengthening stage, crack strengthening stage, plastic softening stage and residual strength stage. The joints of rock masses with different roughnesses have different types of failure during the shearing process, and the shear failure of rock masses can be roughly divided into three types under the constant normal load, which are slip failure, local shear failure and gear cutting failure.