关键词: 高静应力, 动静载耦合, 动态响应, 上行开采

Abstract: The dynamic response of rock in high stress state under low-frequency disturbance load are important factors affecting the stability of interlayer strata during upward mining in residual mining area. Brazilian splitting test on sandstone in high stress state under dynamic and static load coupling was carried out using the self-developed dynamic and static load coupling test machine. The effect of low frequency disturbance load amplitudes on the mechanical response characteristics of high static stress sandstone was analyzed. The results show that: 1) The sandstone in high stress state will not be destroyed in the process of small disturbance load, but the disturbance damage will reduce the tensile strength of rock specimens. Therefore, the appropriate reduction factor should be introduced into the upward mining stability analysis based on the static mechanical parameters of interlayer rock. 2) The fatigue life of sandstone decreases with the increase of the amplitude of the disturbance load. The average number of dynamic load cycles before failure of the sandstone subjected to the load the amplitude of 5.0, 7.5 and 10 kN is 157, 70 and 3, respectively. 3) The “turbulence” describing the fluid state is introduced to visualize the fast input and output of additional energy in the process of disturbance load. The additional energy flow in the state of “turbulence” weakens the orderliness of sandstone crack propagation, and induces large-scale crack propagation at the moment of sandstone failure. The research results can provide certain reference for the stability analysis of upward mining in residual mining area.

Key words: high static stress, dynamic and static load coupling, dynamic response, upward mining