距离下保护层开采防冲机理及技术研究

针对七台河矿区某矿煤层群的地质赋存特点，研究了近距离下保护层开采防治冲击地压的机理和技术。利用FLAC 3D软件，分析比较了下保护层开采和非保护层开采的工作面围岩应力应变及塑性范围的分布规律及其差异，揭示了近距离下保护层开采的防冲机理，并讨论了下保护工作面的合理布置。结果表明近距离下保护层开采能取得较好的防冲效果，近距离下保护层开采防冲的机理是：下保护层开采降低了被保护工作面的应力峰值，使应力峰值位置向煤体深部转移；增大了被保护工作面围岩的位移，有利于释放冲击弹性能；被保护工作面的围岩预先产生塑性变形，在掘进、回采中不易再次发生塑性破坏。当被保护工作面布置合理时，能取得防冲和留巷的双重效果。

Rockburst prevention mechanism and technique of close-distance lower protective seam mining

According to the geological condition of coal seam group in Qitaihe mining area，the rockburst prevention mechanism and technique of close distance lower protective seam mining were studied.First，by the FLAC3D software，the stress，strain and plastic zone regularity of protective seam mining and non protective seam mining was analyzed and compared.Then，the rockburst prevention mechanism of close distance lower protective seam mining was revealed.Finally，the protective face layout was considered.The results show the close distance lower protective seam mining effective to prevent rock burst，and the rockburst prevention mechanism contains:to reduce the stress peak value，to increase the strain，to avoid the new plastic zone.When the layout of protective face is rational，there can produce the two effects:to prevent rock burst and to retain the existing roadway.