Mechanics of rock-burst induced by thrust fault phased activation under mining disturbance

In order to ascertain the impact of mining disturbance on the complex mechanical interaction mechanism of thrust fault on rock-burst, this paper combines the field data, theoretical derivation and numerical simulation methods to comprehensively analyze the activation process of thrust fault under mining disturbance. From the perspective of dynamic-static loading disturbance, the mechanism of rock-burst induced by thrust fault under the influence of mining was further analyzed. The activation of the thrust fault under the influence of mining is a staged process, and the process can be quantitatively divided into three stages through the slip tendency index Ts:quasi-static, activation, and slippage. The high level fault area is a dangerous area during the activation of the fault, and the degree of danger of the fault activation is affected by the fault dip angle and the distance from the working surface to the fault. The research results show that the mechanism of rock-burst induced by thrust fault under the influence of mining is mainly caused by dynamic and static loading. On the one hand, the decrease of the fault dip angle will cause the concentration factor of the leading support pressure on the working face to increase, increasing the danger of rock-burst. On the other hand, the energy released during the phased fault activation process can be characterized by the seismic moment M0.There is an exponential correlation between M0 and the distance l from the working face to the fault. The p and q values in this correlation can be used to characterize the degree of seismic moment released of the thrust fault during the mining process. The p value reflects the energy released level of the fault at the later stage of mining, and the q value reflects the energy released level of the fault at the early stage of mining. Larger values of p and q indicate a higher degree of fault energy released. The higher the energy released after the fault slips, the greater the impact on the working surface, and the easier it is to induce the occurrence of rock-burst. The analysis found that the p value decreases with the increase of the fault dip angle, and the q value increases with the increase of the fault dip angle. © 2020, Editorial Office of Journal of China Coal Society. All right reserved.