Numerical study of shear behavior of intermittent rock joints with different geometrical parameters

The purpose of this paper is to investigate shear behavior of rock specimens containing several intermittent joints with different geometrical parameters. Through three series of direct shear tests based on rock failure process analysis (RFPA^2D) code, the whole shear failure process is visually observed and the failure patterns in reasonable accordance with other experimental results are obtained. In general, the failure pattern is mostly influenced by the geometrical parameters of rock joints while shear strength is closely related to the failure pattern and its failure mechanism. It is observed that the propagation of wing cracks depends on the joint separation and the joint azimuth angle, and the connection of wing cracks dominates the eventual failure pattern and determines the peak shear load of the rock specimens. The results also show that macro shear fracture is due to the mesoscopic tensile damage of a large number of elements. This numerical study has made a more reasonable theoretical explanation for the shear mechanism of jointed rock due to the inner damages that are difficult to observe in an experimental testing.