浅埋高强度开采回撤巷道煤柱受载特征及累积损伤机制  

Progressive loading characteristics and accumulated damage mechanisms of shallow-buried coal pillars in withdrawal roadways with high-strength mining effect

作　　者：王方田[1,2] 邵栋梁 牛滕冲 窦凤金 WANG Fangtian;SHAO Dongliang;NIU Tengchong;DOU Fengjin(School of Mines,China University of Mining and Technology,Xuzhou,Jiangsu 221116,China;State Key Laboratory of Coal Resources and Mine Safety,China University of Mining and Technology,Xuzhou,Jiangsu 221116,China;Jinjie Coal Mine,Shendong Coal Group Corporation,Yulin,Shaanxi 719319,China)

机构地区：[1]中国矿业大学矿业工程学院,江苏徐州221116 [2]中国矿业大学煤炭资源与安全开采国家重点实验室,江苏徐州221116 [3]神东煤炭集团锦界煤矿,陕西榆林719319

出　　处：《岩石力学与工程学报》2022年第6期1148-1159,共12页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金面上项目(51974297);中央高校基本科研业务费专项资金(2019XKQYMS50)。

摘　　要：为解决浅埋高强度开采回撤巷道护巷煤柱的长期稳定性问题,以锦界煤矿31409工作面末采段回采任务为工程实例,采用力学测试、数值模拟和现场监测等手段,探究开采扰动期间工作面超前支承压力叠加效应和渐进受载条件下通道煤柱的应力演化和累积损伤机制。设计三级循环加卸载条件下煤样强度弱化和损伤破坏实验,揭示末采段采动应力转移历程,构建工作面末采段采动应力响应数值计算模型。研究表明:(1)循环加卸载损伤煤样单轴压缩强度降低至14.14 MPa(无损煤样单轴抗压强度为18.40 MPa),变化率为23%,峰后承载段有载荷波动现象(有别于瞬间破损),在峰值载荷前累积损伤煤样单轴压缩声发射参数保持低值浮动状态,相比循环加卸载3次时裂隙发育活动性略有衰减;(2)末采段采动应力历经常规回采段煤壁超前支承压力反复叠加、临近通道段支承压力持续转移、贯通段多重累积应力释放3种状态,且通道煤柱载荷在辅回撤巷道和采空区间呈现采掘联合影响、不均匀分布特征,获得煤柱稳定临界损伤度评价参数ω;(3)末采段回采空间前后的上覆岩层或煤体内存在支承压力衰减区、极限平衡区和累积增加区,随工作面继续推进采动应力影响范围扩展至覆岩关键层位置,矿压显现剧烈、通道煤柱应力积聚增长,由原岩应力大小逐步增加至7.3 MPa,增长了2.8倍,为确保回撤巷道支护体系稳定和护巷煤柱安全运行提供了理论基础。In order to solve the long-term stability of the shallow-buried coal pillars in withdrawal roadways with high-strength mining effect,the backstoping in the final mining section on the 31409 working face of Jinjie Coal Mine was taken as a project case,and adopting mechanical testing,numerical simulation and on-site monitoring,the stress evolution and accumulated damage mechanism of the coal pillar in the roadway were explored under the superimposed effect of the advanced support pressure on the working face and the progressive loading condition during excavation disturbance.An experiment of coal sample strength weakening and damage failure under three-stage cyclic loading and unloading conditions was designed to reveal the mining stress transfer process in the final mining section,and a numerical model of the mining stress response in the final mining section on the working face was constructed.The research results indicate that:(1)The uniaxial compressive strength of the coal sample under cyclic loading and unloading damage is reduced to 14.14 MPa,while the uniaxial compressive strength of the non-destructive coal sample is 18.40 MPa with a change rate of 23%.There are load fluctuations in the load-bearing section after the peak,which is different from instantaneous damage.The AE parameter of uniaxial compressive of the cumulatively damaged coal sample before the peak load is floating in low values,which is slightly attenuated in the mobility of fracture development compared with that after three loading and unloading cycles.(2)The mining stress in the final mining section experiences three states including repeated superimposition of the advanced support pressure on the coal wall in the conventional mining section,continuous transfer of the support pressure in the adjacent passage section and release of multiple cumulative stresses in the mining run-through section,the passage coal pillar load presents the characteristics of mining-excavation combining influence and uneven distribution in the auxiliary recovery

关 键 词：采矿工程 浅埋煤层 回撤巷道 渐进受载 煤柱稳定性 累积损伤 

分 类 号：TD32[矿业工程—矿井建设]