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大采高工作面锚杆支护巷道局部冒顶机理研究

Research on localized roof falling mechanism of bolt supporting roadway in large mining height working face

  • 摘要: 基于大采高工作面巷道冒顶制约煤矿安全生产的问题,采用现场实测和数值模拟方法研究了巷道局部冒顶的影响因素。现场测试表明:冒顶位置巷道直接顶板为5.8 m泥岩,且为多层复合,锚索锚固端附近存在泥质页岩软弱岩层,黏土矿物占比达54.3% 。锚杆锚固区内外均发生明显离层,支护体受岩层错动发生剪切变形。数值模拟得出,受回采动压未稳定区域掘巷、护巷煤柱尺寸小、支护强度和刚度不足等因素影响,顶板软弱节理面发生离层,支护应力场完整性丧失,围岩塑性破坏后发生冒落。提出在地质异常区及时支护、增大支护强度防止锚固区离层、加强施工质量检测等技术手段,提高巷道安全系数,为减少冒顶事故提供工程借鉴。

     

    Abstract: In view of the problem of coal mine safety production caused by roof fall in large mining height working face, the field measurement and numerical simulation method were used to study the influencing factors of localized roof collapse. Field tests show that the direct roof of the roadway at the location of roof fall is 5.8 m mudstone with multi-layer composite. There is a weak shale rock formation near the anchorage end of the anchor cable, accounting for 54.3% of clay minerals. Significant separation occurs in the anchorage zone of the anchor, and the support body is shear-deformed by the displacement of the rock stratum. The numerical simulation shows that the weak joint surface of the roof is separated, the integrity of the supporting stress field is lost, and the rood fall occurs after plastic failure due to the the factors such as mining under unstable dynamic pressure, small size of the pillar and insufficient support strength and stiffness. It is proposed to timely support in the geological anomaly area, increase the support strength to prevent the anchorage zone from separating, strengthen the construction quality inspection and other technical means, improve the safety factor of the roadway, which provides engineering references in order to reduce the roof accidents.

     

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