关键词: 近直立煤层, 冲击地压, 深浅孔爆破, 卸压效果

Abstract: In order to reduce the horizontal stress concentration degree of near-vertical coal seam working face, the principle of pressure relief by blasting at the top and floor of near-vertical coal seam is analyzed theoretically, and the parameters of deep and shallow hole blasting pressure relief scheme are determined. The effect of pressure relief blasting is analyzed by means of borehole imaging, electromagnetic radiation and micro seismic data analysis. The research results show that: After deep and shallow hole blasting, a three-dimensional "buffer zone" is formed in the rock layer of the roof and floor, which hinders the transmission of high level in-situ stress to the working face and reduces the degree of stress concentration. After blasting, new cracks are developed in the roof and floor, and the number increases by about 46.6%. Some cracks are expanded into bed separation and local broken zones appear. After blasting, the electromagnetic intensity of coal and rock mass on both sides of the working face decreases obviously, and the micro seismic energy and frequency show the law of first increasing and then decreasing before and after blasting, which has played a good effect of pressure relief.