近距离煤层巷道围岩结构力学模型及应力分布规律研究

Study on Structural Mechanics Model and Stress Distribution Law of Roadway Surrounding Rock in Close Distance Coal Seam

针对近距离煤层开采下层煤巷道受到上层煤遗留煤柱影响而产生应力集中和矿压显现剧烈的现象,以西铭矿8#煤层和9#煤层近距离煤层为研究对象,采用理论分析、数值计算的方法,构建了近距离煤层巷道围岩结构力学模型,研究了下层煤单侧采动后不同错距对夹层顶板断裂线位置的影响规律,分析了上层煤遗留煤柱下的应力分布特征,得到了不同巷道支护力下外错巷道的合理布置方式。研究结果表明:外错布置条件下,夹层顶板断裂线位置随巷道错距增加从实体煤柱一侧向采空区一侧移动;内错条件下,呈相反规律;采动前,遗留煤柱下左侧工作面外错巷道的合理错距为2 m,内错巷道的合理错距为6 m;采动后,遗留煤柱下右侧工作面巷道外错布置可减小煤柱损失,外错巷道的合理错距为8 m。

In view of the phenomenon of stress concentration and mineral pressure appearing intensely due to the influence of the coal pillars left by the upper coal in the lower coal roadway in the near coal seam mining,taking the No.8 coal seam and No.9 coal seam near coal seams of Ximing mine as the research object,the structural mechanical model of the surrounding rock of the near coal seam roadway was constructed by theoretical analysis and numerical calculation.The influence law of different staggered distances on the position of fracture line of sandwich roof after single-side mining of lower coal is studied,the stress distribution characteristics under the left coal pillar of upper coal is analyzed,and the reasonable layout mode of external staggered roadway under different supporting forces is obtained.The results show that the fault line of the sandwich roof moves from the solid pillar side to the goaf side with the increase of the roadway fault distance under the condition of external fault layout.Under the condition of internal error,the law is opposite.Before mining,the reasonable deviation distance of the outer and inner fault roadway of the left working face under the coal pillar is 2 m and 6 m respectively.After mining,the loss of coal pillar can be reduced by the layout of the roadway outside the left coal pillar,and the reasonable spacing of the roadway outside the wrong pillar is 8 m.