近距离煤层综放末采关键块体回转机制及其应用  

Rotation mechanism of key blocks during end-mining period of fully mechanized caving in close distance coal seams and its application

作　　者：何富连[1,2] 吕凯 许旭辉 王德秋 李亮 HE Fulian;LV Kai;XU Xuhui;WANG Deqiu;LI Liang(School of Energy and Mining,China University of Mining and Technology(Beijing),Beijing 100083,China;Beijing Key Laboratory for Precise Mining of Intergrown Energy and Resources,China University of Mining and Technology(Beijing),Beijing 100083,China)

机构地区：[1]中国矿业大学(北京)能源与矿业学院,北京100083 [2]中国矿业大学(北京)共伴生能源精准开采北京市重点实验室,北京100083

出　　处：《岩石力学与工程学报》2023年第8期1832-1846,共15页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(51974317);中央高校基本科研业务费专项资金资助(2022YJSNY09)。

摘　　要：为了探究遗留边界煤柱对下位综放工作面末采围岩产生的不利影响,以燕子山煤矿近距离煤层开采为研究背景,将下煤层综放工作面末采期间的覆岩环境归纳为4类,分别为采空区、边界煤柱采空侧、边界煤柱实煤侧和实体煤。通过构建异形载荷作用下关键块体回转速度力学模型,将综放末采关键块体的回转划分为4个阶段,并对各个阶段的临界回转角、合外力矩及角加速度进行求解,基于定轴转动原理,获得块体回转全过程角速度方程,并分析覆岩载荷、顶煤停放距离和基本顶断裂线位置对块体回转速度的影响规律。结果表明:(1)覆岩载荷对块体回转速度的影响程度表现为边界煤柱实煤侧>边界煤柱采空侧>采空区>实体煤。(2)顶煤停放距离本质上分为3类,I类停放距离等效于末采不停放顶煤,II类停放距离仅减小块体B的回转角,不改变其回转速度,III类停放距离同时减小块体B和C的回转角和回转速度。(3)与基本顶断裂线深入煤壁相比,当基本顶断裂线位于回撤通道上方时,回撤通道煤壁及顶板支护结构提供的回转阻力矩减小,块体角速度增大,不利于末采围岩稳定。(4)提出了近距离煤层综放末采矿压防治对策,并对N0381工作面末采围岩控制进行了有效指导,工作面矿压实测结果在一定程度上验证了力学模型的合理性与可靠性。In view of the adverse effects of the residual boundary coal pillar on the surrounding rock of the lower fully mechanized top coal caving face in the end-mining period,taking the close distance coal seams of the Yanzishan coal mine as the research background,the end-mining overburden environment of the lower coal seam is classified into four categories,namely,the gob side of boundary pillar,the solid coal side of boundary pillar,the gob and the solid coal.By establishing the rotation speed mechanical model of key blocks under abnormal loads,its rotation during the end-mining period of fully mechanized top coal caving face is divided into four stages.The critical angle,external moment and angular acceleration of each stage are solved.The angular velocity equation of the whole rotation process of the key block is obtained based on the principle of fixed axis rotation,and the influence law of the overburden load,the top-coal stopping caving distance and the main roof fracture line position on the block rotation speed is analyzed.The research shows that:(1)The influence of the overburden load on the block rotation speed is ranked as:the solid coal side of boundary coal pillar>the gob side of boundary coal pillar>the solid coal>the gob.(2)The top-coal stopping caving distance can be essentially divided into three types.Type I is equivalent to the top coal without stopping,type II only reduces the rotation angle of block B without changing its rotation speed,while type III reduces the rotation angle and its angular velocity of both block B and C.(3)Compared with the main roof fracture line penetrating into the coal wall,the rotation resistance moment provided by the support structure decreases and the angular velocity of block B increases when it is located above the retracement channel,which is not conducive to the stability of the surrounding rock in the end-mining period.(4)The end-mining ground pressure control strategy of fully mechanized top coal caving face in close distance coal seams is proposed,which effectiv

关 键 词：采矿工程 近距离煤层 异形载荷 末采停放 关键块体 回转速度 回撤通道 

分 类 号：TD32[矿业工程—矿井建设]