Mechanism and prevention practice of rock burst in thick and hard roof

Based on the characteristics of thick hard roof and hard coal seam of rock burst mine in Ordos area, the occurrence process of rock burst under the condition of wide coal pillar mining was analyzed. It is revealed that the rock burst in this region is caused by the dynamic system instability in the high stress region of coal body, vibration, stress wave excitation, stress wave interaction with the coal body in the plastic region. Taking Bayangaole Coal Mine as an example, deep hole blasting was used to relieve the pressure on the roadway roof. The results showed that in the area where the roof was not broken, the limit breaking of the roof leaded to large energy micro-seismic events, the energy release was concentrated on the side along the empty roadway, and there was a phenomenon of dynamic pressure on site. In the normal fault roof area, the micro-seismic activity was relatively stable, and the energy concentration area had no direct impact on the roadway. The average pressure period of the working face was 2.4 days, the pressure step was 14.5 m, and there was no continuous high-intensity pressure. The crack of the observation hole in the roof was well developed, and the effective radius could reach 4 m.