Overburden structure evolution for mining in large buried deep isolated island working face and practice of rock burst prevention and disaster reduction

Aiming at the problem of rock burst prevention and control in isolated working faces under deep mining conditions,the 003 deep well isolated working face in the central mining area of Qujiang Coal Mine in Fengcheng, Jiangxi Province was taken as the research object. By combining laboratory tests, theoretical analysis and numerical simulation, a systematic study was conducted on the coal-rock impact tendency of isolated working faces, the structural characteristics of overlying rocks in isolated working faces,and the stress evolution features during the mining period. The test results indicate that the coal seam and floor of the 003 isolated island working face exhibit no burst tendency,while the coal seam roof shows a strong burst tendency. FLAC^3D numerical simulation shows that with the coal face advancing,the stress concentration degree of the coal pillar in the front gradually increases from 1. 05 to 1. 24. Especially during the "square" mining period of mining, the concentration degree is relatively high. On-site roof pre-cracking blasting pressure relief was carried out and tested by the drill cuttings method. This pressure relief scheme effectively weakened the static load level and had a good anti-impact control effect.