Occurrence Mechanism and Prevention Technology of Rock Burst in Middle Layer Mining of Steeply Inclined Thick Coal Seam

Abstract

In view of the frequent occurrence of rock burst in the middle layer of the steeply inclined thick coal seam in Dongxia Coal Mine, based on the three-dimensional microseismic monitoring network and the seismic source space precise positioning method, the law that the seismic source of mine earthquakes is concentrated in the floor rock roadway and its distribution trend line is perpendicular to the direction of maximum horizontal stress is determined; according to this, it is determined that the coal burst in the middle layer is caused by the decrease of the minimum principal stress (vertical direction) caused by the mining of the upper layer, which makes the floor rock reach the Mohr shear failure limit state under the strong tectonic stress, and then the blasting anti-rock burst measures for the floor rock is proposed. The result of engineering practice shows that using reasonable blasting amount of floor regularly can effectively reduce vibration frequency and energy and avoid the occurrence of rock burst.

Keywords

• steeply inclined thick coal seam
• rock burst
• floor rock
• shear fracture
• tectonic stress
• floor blasting