Abstract: The NPR anchor bolt anchoring structural surface exhibits extraordinary shear resistance under static shear loads,but the mechanical response under dynamic cyclic loads still needs further verification. Using processed original rock samples,a pre-peak cyclic loading shear test was conducted on a homogeneous sandstone structural plane. The influence of factors such as cyclic loading times,loading rates,and different amplitudes on the shear strength of the structural plane was compared and analyzed under two working conditions:non anchoring and NPR anchor anchoring. The results show that:① When the number of cycles is 80,the shear strength of the non anchored structural surface reaches its peak;In contrast,the peak shear strength of the NPR anchor rod anchoring structure surface has significantly improved. ② The cyclic loading rate increases from 1 kN/ s to 1. 5 kN/ s,and the shear strength of the non anchored structural plane decreases faster;On the contrary, when the loading rate increases,the peak shear strength of the NPR anchor bolt anchoring structure surface shows a greater improvement. ③ The cyclic loading amplitude increases from 50% τmax to 80% τmax,and the shear strength of the non-anchored structural plane decreases. However,the shear strength of the anchored structural surface of NPR anchor rod increases,effectively improving the brittle failure characteristics of the no-anchored structural surface. ④ Under different normal stresses,the shear strength of the NPR anchor bolt anchoring structure surface is significantly improved compared to the no-anchoring structure surface. The above research results can provide scientific basis for seismic and explosion-proof design of open-pit mining. 

Key words: pre-peak cyclic loading,anchor shear test,rock mass discontinuity,NPR anchor