工作面端头L形区煤柱体诱发冲击机理及防治研究
Research of coal pillar inducing rock burst in L-shaped zone of working face and prevention technology
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摘要: 为了研究深部开采工作面端头L形区煤柱体失稳诱发两类典型的巷帮冲击地压,基于宝积山煤矿705综放工作面5次冲击地压显现与工作面推进位置关系,分析了一定围压条件下煤柱体的受力状态和力学响应,并推导出了煤柱体失稳破坏与作用载荷的关系。利用FLAC3D软件应变软化模型模拟研究了集中静载荷和动载荷组合作用下煤柱体的应力-应变特性,结果表明:初始静载荷变化对煤柱体失稳发生冲击的影响作用要高于动载荷变化,集中静载荷起储存冲击能作用,动载荷起诱发冲击作用。提出锚网索支护+高压水射流巷帮卸压协同作用防治巷道冲击地压方法,模拟分析显示围岩应力分布满足强弱强(3S)三重防冲结构,围岩结构弯矩分布均匀合理。本研究为协同作用防治巷道冲击地压提供了理论依据。Abstract: In order to study the coal pillar in L-shaped zone of working face inducing two kinds of typical rock burst in deep mining,the relation between the position of 705 fully mechanized working face and the corresponding 5 times rock burst records is used to study the stress state and mechanical response of coal pillar under certain confining pressure condition,and the relation between coal pillar unstable failure and load is determined.The stress-strain characteristics of coal pillar under dynamic and static combined load are studied by using the strain-softening model of FLAC3D numerical simulation.The results show that the change of static load has a greater effect than dynamic load on coal pillar unstable failure.The static load plays a role in storing energy,and dynamic load play a role in inducing rock burst.The paper puts forward to use bolt-mesh-cable support and high-pressure water jet unloading combined technology to prevent rock burst in roadways.The numerical simulation results show that stress distribution of surrounding rock meets the model of strong-soft-strong(3S) structure,and the moment distribution is reasonable.The study conclusions provide theoretical foundation and a new guidance for preventing rock burst by synergistic effect technology in roadways.