基于微震监测的双系煤层开采覆岩运动与矿压显现关系

Relationship between overburden strata movement and strata behavior during dual system seam mining based on microseismic monitoring technology

以大同矿区双系煤层开采为研究背景,基于高精度微地震监测技术,研究石炭系特厚煤层8104综放工作面开采过程中上部侏罗系煤层群复杂采空区影响下微震事件时空演化特征,得到双系煤层影响下覆岩运动与矿压显现的关系。结果表明:8104工作面接近和进入上部侏罗系煤层采空区对应区域,8104工作面覆岩运动加剧,侏罗系煤层的开采是工作面覆岩运动加剧的主要原因;侏罗系煤柱重叠区域微震事件密集分布,在工作面的开采扰动和重叠煤柱应力传递的共同作用下,微震总能量和能量大于10~5J的震动次数均处于较高数值,覆岩运动更加剧烈。临近采空区对8104工作面的强烈覆岩运动起到了关键作用,在临近采空区和侏罗系覆岩共同作用下,工作面超前微震事件集中,矿压显现剧烈。工作面开采扰动、临近采空区覆岩运动和侏罗系重叠煤柱的耦合作用,是石炭系综放工作面矿压显现剧烈的根本原因。

With the dual system of coal mining in Datong mining area,the microseismic events space-time evolution characteristics under the influence of complex mined-out area at the upper Jurassic coal seam group during fully-mechanized caving mining at the 8104 coal face in the Carboniferous extremely thick coal seam was investigated based on the high accuracy micro seismic monitoring technology. The relationship of strata movement and rock pressure under the influence of double series coal seams was obtained.The results show that the strata movement of the 8104 working face was enhanced when the 8104 face was close to the corresponding area under the upper Jurassic coal goaf.The coal mining working face in the Jurassic is the main reason for the increase of strata movement at the 8104 coal face. The distribution of seismic events was concentrated at the area with the Jurassic coal pillars overlap,the mining disturbance and the coal pillar overlap in the working face transferred stress,thus the vibration frequency with the total energygreater than 10~5 J was still high.Closing to goaf played a key role in the strata movement at the 8104 working face.Microseismic events in advance at the 8104 coal face were concentrated under the joint action of the adjacent goaf and the Jurassic strata,and the mine pressure appeared sharp.The coupling effects of working face mining disturbance,adjacent goaf strata movement and the Jurassic overlapping coal pillar were the root cause of the mine pressure intensity at of the Carboniferous full-mechanized caving mining face.