(1. State Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering，China University of Mining and Technology，Xuzhou，Jiangsu 221116，China；2. State Key Laboratory for Tunnel Engineering，China University of Mining and Technology(Beijing)，Beijing 100083，China；3. Transportation Industry Key Laboratory of Highway Construction and Maintenance Technology in Loess Areas，Shanxi Provincial Transportation Technology Research and Development Co.，Ltd.， Taiyuan，Shanxi 030032，China；4. Guangxi Road and Bridge
Engineering Group Co.，Ltd.，Nanning，Guangxi 530012，China)
Abstract：The interfaces between anchor cable，anchoring agent and the surrounding rock are weak areas in anchoring systems. Focusing on the debonding failure characteristics under cyclic disturbance action，this study established an equivalent shear mechanics model for the anchoring system and conducted cyclic shear tests. The influences of rock lithology，normal load (Fs)，cyclic shear displacement amplitude (ud) and cycle number (N) on the shear mechanical properties of the anchoring system were studied. The experimental results indicate that the anchoring system experiences progressive accumulation of damage during the cyclic shear stage，with the maximum shear force (Fhpeak) generally presenting a decreasing trend with N. As ud increases，the location of the maximum shear force of the anchoring system gradually transfers from the direct shear stage to the cyclic shear stage. The peak shear force (Fhmax) and residual shear force (Fhres) decrease by 28.46%‐54.13% and 21.22%‐49.25% respectively. An increase in the rock strength and normal load strengthens the shear resistance characteristics of the anchoring system. In the cyclic shear stage，the sustained wear and degradation at the interface result in a more pronounced normal shear contraction within the anchoring system. Conversely，in the direct shear process，the climbing effect of the through fracture plane leads to gradual prominence of the normal shear dilation. The overall shear contraction of the anchoring system is gradually enhanced with an increase in ud and Fs，while weakened with the increasing rock strength. Three typical shear failure modes of the anchoring system are identified：internal shear fracture through the coal matrix，debonding failure and fracture of the anchoring agent-sandstone interface，and debonding and slip of the anchor cable-anchoring agent interface in the limestone anchoring system. The whole process of shear fracture surface formation and debonding failure evolution of the anchoring system is discussed based on the digital photography.
