浅埋厚基岩下二次采动巷道变形机理与控制技术

Deformation mechanism and control technology of secondary mining roadway deformation under shallow buried thick bedrock

以锦界煤矿31302综采工作面为研究对象,运用现场分析、数值模拟等方法对浅埋厚基岩顶板下受二次采动巷道强矿压显现规律和控制技术进行研究。31302工作面开切眼处顶板厚且坚硬,基本顶分层垮落导致初采时工作面出现先弱后强的来压规律,机尾侧矿压显现明显,上区段煤柱侧采空区顶板悬露长,煤柱集中应力大,31302回采过程中基本顶在机尾侧20~30架断裂,巷道围岩发生剧烈变形;工作面过富水区时煤层比较破碎,节理裂隙发育,受采动影响时易出现片帮现象,煤层片帮深度越大,空顶面积越大,易发生顶板变形、冒落事故。综上所述,可从补强支护加固煤柱强度、使用高强度超前支架减小上区段悬顶对煤柱产生的应力两方面入手,当顶板坚硬时,必须采取超前水预裂、退锚等措施控制悬顶面积,减小煤柱集中应力,为下区段工作面回采创造条件。

Taking the 31302 comprehensive mining face of Jinjie Coal Mine as the research object,using on-site analysis,numerical simulation and other methods to investigate the manifestation law and control technology of strong mining pressure under the secondary mining roadway deformation under the shallow buried thick bedrock roof.The opening cut at the top plate of the 31302 working face is thick and hard,the collapse of the basic roof layer resulted in a weak to strong pressure pattern on the working face during initial mining,the mining pressure on the tail side of the machine is obvious,and the hanging roof of the goaf on the upper section of the coal pillar side is long,the concentrated stress in the coal pillar is high.During the mining process of 31302 working face,20-30 fractures occurred on the tail side of the machine,which causing severe deformation of the surrounding rock of the roadway.The coal seam is relatively fragmented and has developed joints and fissures when the working face passes through the rich water area,when affecting by mining,it is easy to encounter the phenomenon of roof caving,the deeper the caving depth of the coal seam is,the larger the area of the empty roof is,which is prone to roof deformation and collapse accidents.In summary,the paper starts from two aspects,strengthening the support and strengthening the coal pillar strength,and using high-strength advanced supports to reduce the stress caused by the hanging roof of the upper section on the coal pillar,when the top plate is hard,measures such as advanced water pre splitting and anchor retreat must be taken to control the overhanging area,reduce the concentrated stress in the coal pillar,and create conditions for the mining of the lower section working face.