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悬顶结构巷道冲击地压防控研究

Research on prevention and control of rock burst in entry with suspended roof structure

  • 摘要: 为解决沿空侧悬顶结构冲击地压的防控问题,针对某矿工作面具体煤岩层条件,提出了基于工程弱结构体的冲击地压防控方法。基于悬顶类巷道冲击地压发生条件,以沿空侧悬顶结构为主要研究对象,进行了顶板断裂分析、参量分析和力学模型建立与分析,最终确定出悬顶结构的悬跨度l是导致存在悬顶结构沿空巷道发生冲击地压主导因素。通过分析主导因素,基于沿空侧巷道围岩的空间结构特点,划定出悬顶结构(区域A)、沿空侧巷道顶板(区域B、C)、沿空侧巷道煤体(区域D)以及巷道近场煤岩体(区域E)5个强结构区域,并提出以区域A爆破弱化为主要防控手段的工程弱结构体冲击地压防控方法;根据区域的结构特点和防控目的,主要针对强结构区域A、C、D、E,制定了悬顶结构弱化、巷道断面恢复和顶板缺陷体与煤层海绵体的耦合3个方面的具体工程弱结构体防控方法。为验证防控技术有效性,以某巷道为对象,现场实施了工程弱结构体展开防控,并于后续采用钻屑法进行了冲击地压防控效果检验。研究结果表明:基于工程弱结构体的耗散机制的研究,通过对悬顶结构弱化、沿空巷道煤体及部分顶板的弱化,实现了冲击地压的有效防控,保障了工作面安全回采;通过现场监测,得出1~3 m处钻屑量最大为2.6 kg/m,4~7 m处最大为2.8 kg/m,7~12 m处最大为5.4 kg/m,均未超过临界标准值,冲击地压危险得以消除。

     

    Abstract: In order to solve the problem of rock burst prevention and control of suspended roof structure along gob, a method for the prevention and control of rockburst based on the engineering weak structure was proposed according to the specific coal and rock conditions of entry. Based on the occurrence conditions of rock burst in the entry with suspended roof, taking the suspended roof structure along the gob side as the main research object, the roof fracture analysis, parametric analysis and mechanical model establishment and analysis were carried out, and finally it was determined that the hanging span l of the hanging roof structure was the leading factor leading to rock burst in the roadway along gob of the overhanging roof structure. Through the dominant factors and based on the spatial structure characteristics of the surrounding rock of the roadway along the gob side, five strong structural regions of the overhanging roof structure ( region A ), the roof of the roadway along the gob ( region B, C ), the coal body of the roadway along the gob side ( region D ) and the near-field coal and rock mass of the roadway ( region E ) were delineated, and the prevention and control method of the rock burst of the engineering weak structure body with the weakening of regional A blasting as the main prevention and control means was proposed;according to the structural characteristics of the area and the purpose of prevention and control, mainly for the strong structural areas A, C, D, and E, three specific engineering weaknesses were formulated, including the weakening of the overhang structure, the restoration of roadway section and the coupling between the roof defect and coal seam sponge. In order to verify the effectiveness of the prevention and control technology, taking the specific stope conditions of a mine as the object, 〖JP2〗the prevention and control of engineering weak structures was carried out on the site, and the drill cutting method was used to test the prevention and control effect of rock burst. The research shows that based on the study of dissipation mechanism of weak structure, the effective prevention and control of rock burst are realized through the ′weakening′ of overhanging roof structure, the ′weakening′ of coal body and part of roof along gob roadway, and the working face is recovered safely. Through on-site monitoring, it is found that the maximum cuttings volume is 2.6 kg/m at the depth of 1-3 m, 2.8 kg/m at the depth of 4-7 m, and 5.4 kg/m at the depth of 7-12 m, all of which do not exceed the critical standard value, and the danger of rock burst is eliminated.

     

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