上覆残采煤层不均衡空间结构冲击致灾研究
Study on disaster caused by unbalanced spatial structure impact of overlying residual coal seam
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摘要: 为分析某矿上部不均衡空间对下部回采工作面在开采过程中的冲击危险性影响,采用物理相似模拟实验结合现场微震波速反演,得出以下规律:①工作面覆岩的运移都呈现倒“U”型分布形态,下层工作面推近上部不均衡开采空间时,裂隙有明显向前发育现象;②下部工作面开采至上层煤开切眼正下方时,下层工作面上覆岩层突然发生垮落,工作面前方与覆不均衡开采空间面影响区域贯通,表明在上部不均衡开采空间开切巷处附近为最危险区域;③结合相似模拟上覆空间结构破断活动特征以及微震能量分布特征获得的煤体应力演化规律,得到在距上覆不均衡空间结构区0~80 m具有强冲击危险性,冲击致灾性高;④分析现场微震波速反演,下层工作面在距上层工作面200 m范围开始,应力集中区域由W1123下平巷逐步向上平巷转移,直至到上部不均衡开采空间开切眼处应力集中程度达到最大,通过开切眼后,应力显著减小。Abstract: In order to analyze the impact of the unbalanced space in the upper part of a mine of Shenxin Company on the impact hazard of the lower working face during the mining process,physical similar simulation experiments combined with on-site microseismic wave velocity inversion were used to draw the following rules:①the migration of the overburden in the working face all presents an inverted U-shaped distribution. When the lower working face approached to the unbalanced mining space at the upper part,the cracks develop obviously forward; ②when the lower working face is mined just below the upper coal cut,the overlying strata on the lower working face suddenly collapses,and the front of the working face is connected to the affected area of the unbalanced mining space,indicating that the most dangerous area is near the roadway cut in the upper unbalanced mining space; ③combining the similar simulations of the overlying spatial structure breaking activity characteristics and the microseismic energy distribution characteristics of the coal body stress evolution law obtained,it can be concluded that there is a strong impact risk and high impact hazard within the range of 0-80 m from the overlying unbalanced spatial structure area; ④analyzing the field microseismic wave velocity inversion,the lower working face starts at a distance of 200 m from the upper working face,and the stress concentration area gradually shifts from the W1123 lower channel to the upper channel until the stress concentration reaches the maximum at the opening of the upper unbalanced mining space. After cutting through the roadway,the stress is significantly reduced.