孤岛煤柱条件下冲击危险工作面终采线位置优化设计

    Research on optimal design of stop line position in working face with rock burst hazard under condition of isolated coal pillar

    • 摘要: 针对姚桥煤矿采区下山孤岛保护煤柱,工作面回采末期微震释放总能量、频次持续上升,现场冲击危险性增强的现象;基于理论分析和数值模拟分析了孤岛煤柱区应力分布形态及工作面开采前后煤柱区应力分布特征;结合工作面开采条件,优化了工作面终采线位置。研究表明:工作面回采前采区孤岛煤柱应力分布特征呈“马鞍形”分布,当工作面走向开采尺度大于920 m时,煤柱区支承应力曲线由“马鞍型”逐渐向“单峰型”过渡,煤柱区应力集中系数从2.20升高到2.56。现场实践表明:工作面走向实际回采尺度900 m,比原设计停采线提前30 m停止回采,该工作面区段保护煤柱宽度由175 m增加至205 m,煤柱区应力呈“马鞍形”分布,有效保障了工作面安全生产,降低了采区保护煤柱区应力集中度,为后续工作面开采创造了有利条件。

       

      Abstract: Aiming at the condition of the downhill islanding protection coal pillar in Yaoqiao Coal Mine, the total micro-seismic energy and the frequency continue to rise at the end of the mining face, and the on-site rock burst risk increases. Based on theoretical analysis and numerical simulation, the stress distribution pattern of the coal pillar area in the island and the characteristics of the stress distribution in the coal pillar area before and after the mining of the working face were analyzed. According to the working face mining conditions, the stop line position of working face was optimized. The study shows that the stress distribution characteristics of isolated coal pillar before the mining of the working face are saddle shape. When the mining scale of the working face is greater than 920 m, the supporting stress curve of the coal pillar area gradually changes from saddle shape to a single-peak pattern, and the stress concentration coefficient of the coal pillar area increases from 2.20 to 2.56. Field practice shows that the actual mining scale of the working face is 900 m, which is 30 m ahead of the original design stopping line. The width of the protective coal pillar in the working face section increases from 175 m to 205 m, and the stress in the coal pillar area is saddle-shaped. It effectively ensures the safety of the working face, reduces the stress concentration in the protective coal pillar area of the mining area, and creates favorable conditions for the subsequent mining of the working face.

       

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