Research on Critical Depth of Rock Burst in Coal Mines in China

Abstract With increasing coal mining depths in China, the number of mines experiencing rock burst is increasing. The conditions in which a mine can reach the critical impact-mining depth remain theoretically unknown, which hampers the determination of the depth at which rock burst prevention can begin in coal mines. Based on different mining boundary conditions of rock bursts occurring in coal mines, this study proposes the concepts and calculation methods of three critical depths of rock bursts in coal mining. The strength criterion for rock mass impact of medium–hard and hard coal is used to evaluate the failure strength and stress state of the coal rock mass under dynamic loading conditions. Then, the value of the dynamic stress coefficient of the coal rock mass is determined. The research team applied this method to numerous mines in China to test rock bursts under different types of working face conditions with a coincidence rate of 100%. Results verify the rationality of the calculation formula of the critical impact depth and the value of the dynamic stress coefficient. The findings of this research can provide a basis for evaluating rock bursts.