厚硬冲击煤层宽煤柱诱发冲击地压机理及防治
Mechanism and Prevention of Rock Burst Induced by Wide Coal Pillar in Thick Hard Coal Seam
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摘要: 针对呼吉尔特矿区厚硬冲击煤层宽煤柱诱发冲击地压现象,通过现场实测和数值模拟,分析了宽煤柱垂直应力分布特征,通过理论分析,揭示了宽煤柱发生冲击的结构条件;基于冲击地压“三因素”机理,研究了宽煤柱诱发冲击地压机理:在侧向支承压力和工作面采动应力叠加影响下,具有冲击倾向性的宽煤柱应力高度集中,当其达到极限强度发生卸载时,由于煤柱体刚度与顶板岩层刚度相近,造成煤体运动速率很大,呈现冲击地压显现。在此基础上,提出了小煤柱护巷和断顶爆破等措施降低煤柱应力、采用大直径钻孔卸压和煤层注水等措施改变煤体刚度的防治策略,针对311103工作面提出了采取断顶爆破和大直径钻孔的组合防治方法,宽煤柱应力集中程度出现明显降低,防治效果较为显著。Abstract: Aiming at the phenomenon of rock burst induced by wide coal pillars in thick hard coal seam in Hujierte Mining Area, the distribution characteristics of vertical stress of wide coal pillar has been analyzed by means of field measurement and numerical simulation. The structural condition of rock burst induced by wide coal pillars has been revealed by means of theoretical analysis. Based on the “three factors” mechanism of rock burst, the rock burst mechanism of wide coal pillar are studied and the results are as follows: accumulated lateral support stress and the advanced abutment stress of working face, the stress of the wide coal pillar is highly concentrated. When the ultimate strength of the coal is unloaded, the coal cylinder body is moving at a high rate due to the stiffness of the coal pillar and the stiffness of the roof rock. On this basis, the prevention strategies that reducing the stress of coal pillar, such as small coal pillar roadway protection and broken roof blasting measures, and reducing the stiffness of coal body, large diameter boreholes and coal seam water injection are proposed. The combined prevention methods, broken roof blasting and large diameter boreholes, are proposed to reduce the stress concentration of wide coal pillar, and the control effect is more significant.