特厚煤层综放开采矿压显现规律的采厚效应研究

Research on mining thickness effect of underground mine pressure behavior by fully-mechanized caving mining in extra thick coal seams

针对特厚煤层综放工作面矿压显现强烈,且对于矿压显现与煤层采厚间关系认识不足的问题。以芦子沟煤矿3106特厚煤层综放工作面为背景展开研究,首先对采厚为17 m和30 m两种特厚煤层高强度开采条件下支架工作阻力进行了监测分析,研究结果表明:2种条件下矿压显现规律具有一定的相似性。通过室内物理相似模拟试验建立了2种采厚条件下大空间采场覆岩结构力学模型,并分析了其对矿压显现的作用机制,指出采厚30 m时覆岩呈"下位直接顶悬臂梁-上位直接顶简支梁-基本顶铰接岩梁"的结构特征,使得直接顶和基本顶回转变形对支架作用力不增反减,导致矿压显现规律并没有随煤层厚度增加而变得强烈。

The underground pressure behavior is stronger at fully-mechanized coal face in extra thick coal seam and knowledge about relationship between mining pressure and mining thickness is insufficient.This paper studied the fully-mechanized coal face in No.3106 extra thick coal seam of Luizgou Coal Mine.First of all,working resistance of suppurt at two different high-intensive exploitation extra thick coal seams,which were 17 m and 30 m respectively,were tested and it was found that two underground pressure behaviors shared similarities.Then,an indoor physical similar simulation experiment was made by building a mechanical model of overlying rock in large space under two conditions.By analyzing its action mechanism on underground pressure behavior,it is indicated that in the mining thickness of 30 m,the overlaying strata features'the lower coal seam supporting the cantilever beam-the upper coal seam supporting the free beam-the main roof jointing the rock beam'.The special construction makesthe immediate roof and the main roof deformed by rotation,and their acting force to brackets decrease,which explains why the underground pressure do not get stronger when the coal seam get thinker.