Numerical Investigation of Granite Failure Mechanism Based on Finite Element Voronoi Grain-based Model

Rock experiments in laboratory can be used to analyze the general law of rock failure from a macroperspective, but it is difficult to study the fracture characteristics of rock joints under the microscale. Therefore, the numerical simulation method has become an important way to study the failure characteristics of rock at the macro-and microperspective. Since the micrograin structures of brittle rocks such as granite are similar to a Voronoi polygon, a Voronoi grain-based model is established based on the RS2 finite-element numerical simulation software to simulate uniaxial and triaxial compression experiments of granite and to explore the influence of confining pressure and joint parameters on the macromechanical parameters and the failure mechanism of rock from the microperspective. The deformation and failure characteristics of granite are studied comprehensively by comparing the simulation result of the Voronoi grain-based model based on RS2 with the result of laboratory experiment and the particle flow code (PFC) simulation one. The influence of different confining pressures on rock failure is obtained by comparing uniaxial compression experiments with triaxial compression studies. Through the repeated calibration of joint parameters and numerical calculations, a set of joint microparameters is obtained, which is close to the macromechanical parameters obtained from laboratory experiments, and then the influence of joint microparameters on the macroparameters of rock is explored. By comparison with other discrete element numerical models, the Voronoi grain-based model based on RS2 is more convenient. The finite-element method has higher calculation efficiency, and the simulation results are closer to the failure characteristics of the rock.