高应力煤柱多关键层断裂诱冲机理及防治
Mechanism and Prevention of Rock Burst Induced by Multi-key Layer Fracture of High Stress Coal Pillar
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摘要: 针对上覆多关键岩层控制条件下,高强度开采的大区段煤柱冲击地压防控技术难题,采用数值模拟、关键层分析和微震监测等方法对某矿31102工作面回风巷区段煤柱冲击地压发生机理及防控方法进行研究。结果表明:回风巷区段煤柱处于高静应力作用下,最高应力集中系数为3.02;工作面上方存在多个关键层,关键层断裂时产生大量微震事件,并以附加动应力形式作用于煤柱,当动应力与静应力之和大于煤柱强度时,煤柱发生冲击。提出了“大直径钻孔预卸压+二次斜交钻孔临场解危卸压”的防治措施,现场实测数据表明方案有效可靠。Abstract: Aiming at the technical problem of preventing and controlling the large section coal pillar rock burst of high-strength mining under the control condition of overlying multi-key strata, the mechanism and prevention and control methods of coal pillar rock burst in the return air roadway section of 31102 working face of a mine were studied by means of numerical simulation, key strata analysis and micro seismic monitoring. The results show that the maximum stress concentration factor of coal pillar is 3.02 under the action of high static stress in the return air roadway section; there are many key strata above the working face, and a large number of micro seismic events occur when the key strata break, and act on the coal pillar in the form of additional dynamic stress. When the sum of forces is greater than the strength of the coal pillar, the coal pillar will be impacted. The preventive measures of “pre-pressure relief of large diameter boreholes + on-site pressure relief of secondary oblique boreholes” are proposed. The field measured data show that the scheme is effective and reliable.