Study on shear failure characteristics of inclined jointed rock mass based on different anchorage angles

Aiming at the problem of anchoring support in inclined jointed rock mass roadway，in order to obtain better anchoring support effect，taking the transportation roadway in 1301 working face of Great Wall No. 6 Mine as the engineering background，based on similar simulation test and numerical simulation analysis，the shear failure characteristics of inclined jointed rock mass with different anchoring angles are revealed. The results show that with the increase of normal load，the peak strength of anchorage body increases gradually. Under the normal load of 4 MPa，with the increase of anchorage angle，the peak shear strength and residual strength both increased first and then decreased，and reached the maximum at 45°. With the decrease of anchorage angle，the pressure chains on both sides of the anchor gradually increase，and tension chains are gradually generated inside the anchor，that is，with the decrease of anchorage angle，the anchor gradually plays the role of axial stretching and sliding suppression，and the anchoring effect of jointed rock mass is gradually improved，and the sliding suppression effect is better when the anchorage angle is 45°. Based on the analysis of displacement evolution law，it is concluded that when the anchoring angle is large，most anchors do not play a shear role，and the ability to limit particle displacement around the anchor is poor，and the anchoring effect is not obvious. When the anchoring angle is small，the ability to limit particle displacement around the anchor is strong and the anchoring effect is good. On the basis of analysis，the evolution laws of shear strength，crack propagation and internal displacement of jointed rock mass，as well as the evolution laws of internal contact force and stress tensor of jointed rock mass are obtained. When the anchoring angle is 45°，it shows better anchoring support effect. © 2023 Power System Technology Press. All rights reserved.