弹性薄板理论在地下采场顶板变化规律研究中的应用

APPLICATION OF ELASTIC THIN PLATE THEORY TO CHANGE RULE OF ROOF IN UNDERGROUND STOPE

以大同矿务局四老沟煤矿8402工作面为工程背景,根据地下采场中围岩结构和岩体中存在着各种结构面的力学特征,假设关键层沿工作面方向上被结构面族分割成一系列相互作用的矩形岩板,以此建立弹性薄板组的力学模型;应用数值模拟技术研究该模型的挠曲和应力分布,结合工程现场实测数据,总结出来压时沿工作面方向上工作面中部极限强度较小的岩板首先发生破断,相邻岩板的支承边界变得不利,随着工作面的推进和载荷的增大,相邻岩板相继破断,依此类推直至岩板破断到工作面两端的关键层破断规律;合理解释工作面中部的支架工作阻力大于其端部支架工作阻力的现象和关键层来压比较强烈的原因。

Based on the engineering background of No.8402 stope in Silaogou coal mine of Datong miner bureau,considering the surrounding rock structure in the stope and mechanical property in rock bodies with various kinds of homogeneous joint planes,an assumption that key roof is divided into a series of interacting rectangular rock plates is presented,then according to the thickness of key roof and its material characteristics,a mechanical model of elastic thin plate group is set up.The deflection and the stress of the model are analyzed by the finite element analysis software ANSYS.After comparison between the results from numerical modeling and those from field engineering,the following rules are generalized:(1) along the stope,the rock plate with relatively small ultimate strength breaks first,(2) for the load transfers and the supporting boundary becomes adverse,the adjacent plates break in turn during the advance of the stopet,he rest may be deduced by analogy,and(3) key roof will break up to the two ends of the stope.At the same time,the phenomenon that resistance in middle bearer is larger than those at the two ends is fairly explained,and an appropriate reason is given to explain the phenomenon that mine pressure in the surrounding rock is relatively big and accompanies a relatively intense phenomenon when the key rock breaks in the stope from the view of material characteristics.