Evaluation of focal mechanism and inducing burst ability of large energy mine earthquakes in deep thick overburden mine

Deep thick overlying strata mine often faces frequent occurrence of mine earthquake during mining, among which large energy mine earthquakes may induce rock burst. In order to investigate the burst inducing ability of large energy earthquakes, based on the engineering background of the 3106 working face of Menkeqing Coal Mine in Ordos mining area, the vertical height of large energy mine earthquakes is modified based on the moment tensor mechanics mechanism, the temporal and spatial distribution characteristics of large energy mine earthquakes are analyzed, and the factors influencing the frequent occurrence of large energy mine earthquakes near the goaf side are explored combined with drilling data. Based on the moment tensor inversion method, the mechanical types and focal mechanisms of large energy mine earthquakes under the condition of thick overlying strata are studied. The results show that the large energy mine earthquake is caused by the fracture of the low thick overburden on one side of the production wall of the working face, and the focal mechanism is mainly tensile fracture type, and a few are compression fracture type. Based on the attenuation law of vibration wave, the large energy mine earthquake attenuation model is established, and the 12 large energy mine earthquakes produced during the mining of 3106 working face are divided into three types. The FLAC3D numerical model is established according to the field support and mining conditions, and the peak particle vibration velocity (PPV) of the roadway near the goaf side of 3106 working face is 0.35 m/s by using the dynamic calculation method. Further, according to the established relationship model of energy E, propagation distance r and PPV, the calculation and analysis confirm that except the second type has a certain influence on the roadway, the other two types of the large energy mine earthquake burst inducing ability is weak, which explains the reason why there is no damage at the site. The research results provide theoretical support for the generation mechanism and induced burst ability analysis of large energy mine earthquakes under similar thick overburden conditions.