近距离特厚煤层采动影响下底板破坏及巷道稳定性研究

Research on Floor Failure and Roadway Stability Under the Influence of Mining in Near-distance Extra-thick Coal Seam

以开采平朔煤矿近距离特厚煤层过程中底板巷道的稳定性为研究背景,通过理论分析、数值模拟及现场实测,对采动影响下的底板变形和破坏规律进行探讨。结果表明:工作面底板破坏深度理论计算值为18.4 m(<煤层间距35 m),底板巷道的顶板较为完整,该结果与钻孔窥视仪实测结果相一致。数值模拟结果发现,随着工作面的推进,工作面的底板破坏深度不断增加,破坏范围不断扩大,当工作面推进100 m时,采动影响造成的底板最大破坏深度达到16 m,应力峰值和应力集中系数分别为16 MPa、3.2。随着工作面向前推进,巷道两帮移近量、顶底板移近量受采动影响的变形规律可分为3个阶段,即缓慢增加段、快速增加段、稳定变形阶段,在-100 m~-50 m范围内,采动对巷道变形影响较小,巷道变形增加缓慢;在-50 m~50 m范围内,采动对巷道变形影响十分强烈,变形呈现快速增加;在50 m~100 m范围,采动效应较弱,巷道变形保持稳定。

Taking the stability of floor roadway in the process of mining the near-distance extra-thick coal seam in Pingshuo Coal Mine as the research background,through theoretical analysis,numerical simulation and field measurement,the floor deformation and failure laws under the influence of mining were discussed.The result shows that,the theoretical calculation value of floor failure depth of working face is 18.4 m(less than coal seam spacing of 40 m),and the roof of floor roadway is relatively complete.The result is consistent with the measured result obtained by borehole peeper.The numerical simulation results show that with the advance of the working face,the floor failure depth and failure scope of the working face are increasing.When the working face has advanced 100 m,the maximum floor failure depth under the influence of mining is 16 m,and the peak stress and stress concentration factor are 16 MPa and 3.2 respectively.With the advance of the working face,the deformation law of displacement at the two sides,the roof and the floor under the influence of mining can be divided into three stages,namely,the slow increasing stage,the fast increasing stage and the stable deformation stage.Within the range of-100 m~-50 m,the mining has little influence on the deformation of the roadway,and the deformation of the roadway increases slowly.Within the range of-50 m~50 m,the deformation of the roadway was strongly influenced by the mining,and the deformation increases rapidly.Within the range of 50~100 m,the influence of mining is weak,and the roadway deformation remains stable.