Numerical simulation on crack propagation of rock mass with a single crack under seepage water pressure

The fracture characteristics of fractured rock mass have important significance in environmental geotechnical engineering. Taking a single crack rock mass with dip angle of 45 degrees as the research object, we studied the fracture characteristics of fractured rock mass under different seepage water pressures and confining pressures based on Realistic Failure Process Analysis-Seepage. And then, the initial crack strength was derived and the effect of seepage water pressure and confining pressure on the crack propagation of fractured rock mass was analyzed. It was concluded that the mode of the longitudinal splitting failure, the upside-down capital letter "N"-type failure, and the "-"-type failure were proposed in numerical simulation, which were induced by wing cracks, anti-wing cracks, and secondary coplanar cracks, respectively. In addition, there exists the bifurcation phenomenon of cracks under the seepage water pressure. In theoretical analysis, the initial crack strength increases with the increasing confining pressure and decreases with the increasing seepage pressure, which are in good agreement with the experimental results in the literature. Confining pressure has an inhibitory effect on crack initiation. With the increase in the confining pressure, the successive order of inhibition is wing cracks, anti-wing cracks, and secondary coplanar cracks.