Study on the cyclic shear mechanical properties of anchoring systems containing anchor cable，anchoring agent and surrounding rock

The interfaces between the anchor cable，anchoring agent and surrounding rock represent critical weak points in anchoring systems. This study focuses on the debonding failure characteristics under cyclic disturbance and established an equivalent shear mechanics model for the anchoring system，conducting cyclic shear tests. The influences of rock lithology，normal load(<italic>F</italic>_s)，cyclic shear displacement amplitude(<italic>u</italic>_d) and cycle number(<italic>N</italic>) on the shear mechanical properties of the anchoring system were investigated. The experimental results reveal that the anchoring system experiences progressive accumulation of damage during the cyclic shear stage，with the maximum shear force(<italic>F</italic>_hpeak) generally presenting a decreasing trend as <italic>N</italic> increases. As <italic>u</italic>_d increases，the location of the maximum shear force in the anchoring system gradually shifts from the direct shear stage to the cyclic shear stage. The peak shear force(<italic>F</italic>_hmax) and residual shear force(<italic>F</italic>_hres) decrease by 28.46%–54.13% and 21.22%–49.25%，respectively. An increase in the rock strength and normal load enhances the shear resistance characteristics of the anchoring system. During 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 a gradual increase in normal shear dilation. The overall shear contraction of the anchoring system is gradually enhanced with increases in <italic>u</italic>_d and <italic>F</italic>_s，while it diminishes with 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 at the anchoring agent-sandstone interface，and debonding and slip at the anchor cable-anchoring agent interface in the limestone anchoring system. The entire process of shear fracture surface formation and the evolution of debonding failure in the anchoring system is discussed based on digital photography.