摘要
薄煤层开采条件下巷道复合围岩(煤层和岩层)的稳定与控制是煤矿资源开采的突出问题,深入研究支护结构与煤岩体形成煤-岩-锚组合锚固体的破坏机制具有重要意义。通过对水平方向加锚和未加锚倾斜煤岩组合体(角度设置为15°,30°和45°)试件进行一系列单轴压缩试验,结果表明:无锚试件的应力-应变曲线在峰后阶段有较多微小的多峰起伏波动,出现了应力阶梯式下降;小角度(0°,15°)煤岩组合体破坏时煤体对煤-岩结构面作用的应力较均匀,破坏裂纹主要分布在煤体中,2种角度试件强度差异较小;组合角度增大(>15°),煤体发生拉剪破裂时,对煤-岩结构面形成了局部应力集中,煤体和岩体同时产生拉剪复合破坏,此时煤岩体强度由煤体、岩体以及锚杆共同作用;从环向应变规律来看,煤体与岩体环向应变累积值随组合倾角增加而增大,加锚试件应变累计值小于无锚试件,此外,煤体与岩体二者之间破坏累积发生了滞后效应,煤体提前于岩体50 s进入破坏。最后,对煤-岩-锚组合体力学机制进行探讨,分析锚杆与煤岩体结构面锚固角对煤岩系统强度的变化规律的影响,试验结果与理论预测模型结果比较符合。
The stability and control of roadway composite surrounding rock(coal and rock) under inclined thin coal seam mining is a prominent problem in coal resource mining,and hence,it is of great significance to study the failure mechanisms of coal-rock-bolt composite anchor solid formed by coal,rock mass and the support structure. A series of uniaxial compression tests were carried out on horizontal anchored and non-anchored of inclined coal-rock composite specimens(15°,30° and 45°,respectively). The results show that the stress-strain curves of the non-anchored specimens at the post-peak stage stepwise decrease with many small multi-peak fluctuations. When failure of small-angle coal-rock composite specimens occurs,the stress of coal mass acting on the coal-rock structural plane is more uniform,the failure cracks mainly distribute in coal mass and the strength difference of samples is small. When the combination angle increases(>15°),the local stress concentration is formed on the coal-rock structural plane,and composite tension and shear failures of coal mass and rock mass occur simultaneously. At this time,the strength of coal and rock mass is determined by coal,rock and bolts together. The cumulative value of the circumferential strain of coal and rock increases with increasing the combined inclination,and the cumulative value of the strain of the anchored specimen is less than that of the non-anchored specimen. Additionally,the cumulative destruction between the coal part and the rock part presents a lag effect,and the coal body fails 50 s ahead of the rock mass. Finally,the mechanical characteristics of the"coal-rock-bolt"inclined composite specimens were discussed,and the influence of the anchorage angle between the bolt and the coal-rock structural plane on the strength of the coal-rock system was analyzed. The experimental results are in good agreement with the theoretical prediction model.
作者
余伟健
吴根水
刘泽
黄钟
刘芳芳
任恒
YU Weijian;WU Genshui;LIU Ze;HUANG Zhong;LIU Fangfang;REN Heng(School of Resource and Environment and Safety Engineering,Hunan University of Science and Technology,Xiangtan,Hunan 411201,China;Hunan Provincial Key Laboratory of Safe Mining Techniques of Coal Mines,Hunan University of Science and Technology,Xiangtan,Hunan 411201,China;School of Mechanics and Civil Engineering,China University of Mining and Technology(Beijing),Beijing 100083,China)
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2020年第1期57-68,共12页
Chinese Journal of Rock Mechanics and Engineering
基金
国家自然科学基金面上项目(51974117,51574122)~~
关键词
采矿工程
倾斜煤岩组合体
加锚
非均匀破坏
煤-岩结构面
mining engineering
inclined coal-rock composite specimens
anchored
non-uniform failure
coal-rock structural plane
作者简介
余伟健(1978-),男,2009年于北京科技大学工程力学专业获博士学位,现任教授、博士生导师,主要从事岩石力学与围岩控制等方面的教学与研究工作。E-mail:ywjlah@163.com;通讯作者:吴根水(1993-),男,现为博士研究生。E-mail:Wu_genshui@163.com。
