Rock burst rules induced by cracking of overlying key stratum

The fracture and movement of overlying strata caused by the mining activities have great influence on the behaviors of violent strata such as mining shock and rock bursts. Based on the key stratum theory, the fracture rules of the key strata are studied. When the phenomenon of square “O-X” style caving occurs, the rock pressure reaches its maximum, and as a result, strong mining shock and rock burst easily occur, which is proved by mechanical mechanism. The rule that the most strong tremors with great energy occur in the zone with the overlying key strata caving as square “O-X” is validated by monitoring and analysis results using the micro-seismic observation system. The monitoring results show that the “time-space” evolvement regulation and omen information of the micro-seismic events are obvious. The research achievements establish a foundation for the rock burst forecast method on the basis of the stratum movement theory and micro-seismic observation.