近距离煤层采动影响及巷道合理位置研究

Study on Influence of Close Distance Coal Seam Mining and Reasonable Location of Roadway

为研究近距离煤层下行开采时采动影响规律及下煤层巷道的合理位置,采用FLAC3D数值模拟手段,分析了上煤层开采时覆岩运移规律,研究工作面开采前后邻近巷道及小煤柱应力变化,对比了遗留煤柱下回风顺槽合理布置方式。研究结果表明:上煤层开采顶板扰动影响区域由下向上垂直应力逐渐由“拱形”转化为“梯形”再转化为“双峰”结构,顶板位移曲线向上分布呈现“碗状”结构;上煤层开采对本工作面巷道影响规律相似,下煤层靠近遗留煤柱的回风顺槽受采动影响应力集中更加明显;下工作面巷道采用内错布置式可一定程度减小受上煤层的采动影响,避免遗留煤柱应力集中作用,较外错和重叠布置更加稳定。

In order to study the mining influence law and the reasonable location of the lower coal seam roadway during the downward mining of the close distance coal seam,FLAC3D numerical simulation was used to analyze the overburden transport law during the mining of the upper coal seam,to study the stress changes of the adjacent roadway and small coal pillar before and after the mining of the working face,and to compare the reasonable arrangement of the return wind chute under the leftover coal pillar.The results of the study show that the vertical stresses in the area affected by the roof disturbance of the upper coal seam mining gradually transform from"arch"to"trapezoid"and then to"double-peak"structure,and the displacement curve of the roof shows a"bowl-shaped"upward distribution;the upper coal seam mining has a similar influence on this working face roadway,and the stress concentration is more obvious in the return wind chute of the lower coal seam near the legacy coal pillar;the lower working face roadway adopts the inward staggered arrangement to reduce the influence of the mining of the upper coal seam to a certain extent and avoid the stress concentration of the legacy coal pillar,which is more stable than the outward staggered and overlapping arrangement.