负煤柱长壁工作面底板应力分布及破坏特征  

Stress distribution and failure characteristics of a longwall panel floor with a negative gate pillar

作　　者：王朋飞 刘佳男 冯国瑞[1] WANG Pengfei;LIU Jianan;FENG Guorui(College of Mining Engineering,Taiyuan University of Technology,Taiyuan,Shanxi 030024,China)

机构地区：[1]太原理工大学矿业工程学院,山西太原030024

出　　处：《岩石力学与工程学报》2023年第1期194-211,共18页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(52274092);中国科协“青年人才托举工程”项目(YESS20200211);中国科协科技智库青年人才计划(20220615ZZ07110134)。

摘　　要：为研究负煤柱长壁工作面底板应力分布及破坏特征,采用有限元–离散元耦合数值模拟方法构建FLACPFC数值模型,研究自开切眼、到采空区压实、再到岩层移动稳定全过程底板应力分布时空演化规律、底板破坏特征及矸石堆积对底板受力和破坏的影响,并基于弹性力学理论构建负煤柱工作面底板受力模型,对破坏深度进行理论推导。结果表明:(1)覆岩在采空区两侧形成非对称顶板垮落结构,矸石沿工作面倾向堆积于采空区下部,堆积形态亦非对称,二者共同作用造成底板非对称受力及破坏。(2)底板非对称破坏与顶板关键块回转下沉形成“瓶颈”结构,矸石继续向下堆积受阻。(3)矸石非对称堆积造成底板应力空间上“下大上小”,采空区两侧应力集中随先增强后减弱,底板应力经历压应力-拉应力-压应力演化过程。(4)数值模拟、理论计算及现场实测结果均验证了矸石非对称堆积造成的底板非对称受力及破坏特征。研究可为接续负煤柱长壁工作面巷顶沿空掘巷合理位置选择及围岩控制提供科学依据。To study stress distribution and failure characteristics of a longwall panel floor with a negative gate pillar,coupled finite and discrete element numerical modelling method was adopted to construct a FLAC-PFC coupling numerical model.Spatiotemporal evolution of floor stress distribution,failure characteristics and effect of caved rock accumulation on floor stress and failure were analyzed throughout the process from setup room excavation to compaction of caved rock in gob to roof strata settlement.Based on elastic mechanics,a mechanical floor model was established to derive failure depth.The results show that:(1)Asymmetric accumulation of caved rocks in gob and asymmetric collapse of roof result in asymmetry of stress and failure of floor.(2)A“bottleneck”structure is formed by asymmetric failure of the floor and rotary cave-in of key blocks of roof,which hinders the further asymmetric slip of gob rocks.(3)The floor stress distribution under the influence of asymmetric accumulation of gob rocks presents a spacial distribution of“large top and small bottom”.And the stress concentration on both sides of the gob increases first and then decreases over time,and the floor stress experiences a transition of“compressive-tensile-compressive”.(4)Numerical simulation,theoretical calculation and field measurement results verify the asymmetric characteristics of stress and failure of floor caused by asymmetric accumulation of gob rocks.The study serves to provide theoretical support and scientific basis for determining location of gob side entry and its surrounding rock control of future adjacent panel with a negative gate pillar.

关 键 词：岩石力学 负煤柱 底板 应力分布 破坏特征 矸石滑移 FLAC-PFC耦合 

分 类 号：TU45[建筑科学—岩土工程]