大埋深孤岛工作面回采覆岩结构演化与防冲减灾实践
Overburden structure evolution for mining in large buried deep isolated island working face and practice of rock burst prevention and disaster reduction
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摘要: 针对深部开采条件下孤岛工作面冲击地压防治难题,以江西丰城曲江煤矿中央采区003深井孤岛工作面为研究对象,采用实验室试验、理论分析、数值模拟相结合的方法,对孤岛工作面煤岩冲击倾向性,孤岛工作面覆岩结构特点,回采期间的应力演化特征等进行了系统研究。试验结果表明,003孤岛工作面煤层和底板无冲击倾向,煤层顶板存在强冲击倾向;通过FLAC3D数值模拟发现,随着工作面的推进,前方煤柱应力集中程度从1.05逐渐增至1.24,尤其在回采“见方”期间集中程度相对较高;现场进行了顶板预裂爆破卸压,并通过钻屑法进行检验,该卸压方案有效弱化了静载水平,防冲调控效果良好。Abstract: 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. FLAC3D 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.