矸石充填整体置换“三下”煤柱引起的岩层移动与二次稳定理论  

STRATA MOVEMENT INDUCED BY COAL-PILLAR UNDER THREE CIRCUMSTANCES EXCHANGED BY GANGUE BACKFILL AND QUADRATIC STABILITY LAW

作　　者：余伟健[1,2] 王卫军[1,2] 

机构地区：[1]湖南科技大学煤矿安全开采技术湖南省重点实验室,湖南湘潭411201 [2]湖南科技大学能源与安全工程学院,湖南湘潭411201

出　　处：《岩石力学与工程学报》2011年第1期105-112,共8页Chinese Journal of Rock Mechanics and Engineering

基　　金：湖南省科技计划重点项目(2009FJ2005);湖南省教育厅资助项目(10C0665);湖南省高校科技创新团队支持计划资助项目

摘　　要：根据条带开采特点,针对矸石充填整体置换"三下"煤柱引起的二次岩层移动等问题,首先简述煤柱开采与矸石充填过程,并分析二次岩层移动机制及特征,认为二次岩层移动是由矸石充填支撑体和承重岩层的共同压缩引起的,上覆岩层形成的弯曲带层面为波浪型下沉曲层;然后,根据充填支撑体的实际受力大小和极限强度,采用弹塑性力学及相关理论,推导"承重岩层+矸石充填体"承载体的二次稳定条件、安全系数、极限状态下的软化区宽度以及承载核区宽度的解析式,并给出矸石充填体压缩量w1和上覆承重岩层二次压缩量w2的计算公式,提出二次岩层移动下沉总量计算方法。宝源煤矿的实例计算表明"承重岩层+矸石充填体"承载体的安全系数Fs=1.36,处于稳定状态;"承重岩层+矸石充填体"承载体总压缩量w=0.833 m,矸石支撑体抵抗着较高的应力,维护着上覆岩层结构的二次稳定;数值分析表明,采空区上方应力得到充分释放,充填支撑体上方垂直应力呈马鞍形分布,承重岩层最大下沉位移平均值为0.801 m左右,接近理论计算值。On the basis of strip mining characteristics,the exchanging technology of gangue backfill was described briefly firstly according to subject of strata movement and quadratic stability of coal-pillar under three circumstances exchanged by gangue backfill,mining process of coal-pillar.Mechanism and characteristics of quadratic strata movement were also analyzed.It is considered that the main mechanism is compression of the gangue filling support body and bearing rock strata,and curving belt of overlying strata show the wavy type sinking curved layer.Then,some analytic formulae of the bearing body of＂bearing rock strata ＋ gangue filling support body＂were deduced by means of the elastoplastic theory and based on the actual force and ultimate strength of the gangue filling support body,these analytic formulae includes the quadratic stability condition,the safety factor,the width of plastic area under limit state and the width of bearing core area.Calculation formulae of the compression amount of gangue filling support body（w1） and the quadratic compression amount of bearing rock strata（w2） were got;and the sinking total amount calculation method of quadratic strata movement was put forward too.Theoretical calculation results of Baoyuan Coal Mine indicate that the safety factor of the bearing body of ＂bearing rock strata ＋ gangue filling support body＂Fs = 1.36,and placed in stable state.The sinking total amount w is 0.833 m,the bearing bodies resist against high stress,and maintain quadratic stable of overlying strata.Numerical analysis results show that there is a saddle distribution for above vertical stress of the gangue filling support body;the average value of maximum subsidence displacements of bearing rock strata is about 0.801m,which closes to the theoretical value.

关 键 词：采矿工程 条带开采 矸石充填 “三下”煤柱 岩层移动 二次稳定 

分 类 号：TD322.4[矿业工程—矿井建设]