王方田, 屈鸿飞, 张洋. 深井煤巷帮部围岩剪切滑块理论及防控策略[J]. 煤炭学报, 2023, 48(S1): 47-60. DOI: 10.13225/j.cnki.jccs.2022.0716
引用本文: 王方田, 屈鸿飞, 张洋. 深井煤巷帮部围岩剪切滑块理论及防控策略[J]. 煤炭学报, 2023, 48(S1): 47-60. DOI: 10.13225/j.cnki.jccs.2022.0716
WANG Fangtian, QU Hongfei, ZHANG Yang. Shear slide block theory and its control strategy for coal wall in deep roadways[J]. Journal of China Coal Society, 2023, 48(S1): 47-60. DOI: 10.13225/j.cnki.jccs.2022.0716
Citation: WANG Fangtian, QU Hongfei, ZHANG Yang. Shear slide block theory and its control strategy for coal wall in deep roadways[J]. Journal of China Coal Society, 2023, 48(S1): 47-60. DOI: 10.13225/j.cnki.jccs.2022.0716

深井煤巷帮部围岩剪切滑块理论及防控策略

Shear slide block theory and its control strategy for coal wall in deep roadways

  • 摘要: 针对深井煤巷围岩持续大变形诱发剪切破坏难题,建立了深井煤巷围岩剪切滑块理论力学模型并推导出剪切滑块安全系数,揭示了围岩剪切滑块运动破坏机理。采用极限平衡分析精确解法确定了剪切滑块安全系数数学模型,得出在煤体固有力学特性条件下,黏聚力对巷帮煤体剪切滑块安全系数的影响最大,呈正向线性关系;安全系数随巷高增大而呈指数降低。依据剪切滑块理论模型,以城郊矿深部煤巷为研究背景,采用UDEC软件分析了巷高、黏聚力、节理裂隙及支护方式对剪切滑块运动的影响规律。结果表明:①受采动影响,巷道两帮煤体形成共轭剪切面,出现剪切滑块运动,巷高越大,黏聚力越小,巷道越不稳定;②对于节理发育巷道,裂隙上盘破坏较下盘大,倾角越大时巷道帮鼓越严重,当节理倾角为65°时,帮部剪切滑移块体位移达到0.78 m。裂隙中下部张开,采用锚杆支护时易出现锚杆剪切破坏致使支护失效;③采用帮部斜拉锚索后,有效抑制了裂隙张开,正常发挥了锚杆锚固效果,有节理侧帮部仅鼓出0.14 m。较无支护和使用普通锚杆锚索支护分别减少了83.1%、75.4%,证明增设斜拉锚索对帮部围岩有较好的控制效果。基于剪切滑块理论模型,提出了"防裂-减隙-止滑"协同控制策略,即表层、浅部使用高强高预应力锚杆索及金属网等构件加强支护防止围岩起裂,深部使用注浆改性技术减少围岩裂隙,在严重失稳局部使用斜拉锚索抑制剪切滑块运动,从而使深井煤巷破碎围岩区形成复合承载结构,有效抑制巷道围岩变形。研究成果为深井煤巷围岩稳定性控制提供有益参考。

     

    Abstract: Aiming at the problem of shear failure induced by the continuous large deformation of surrounding rock in the roadway of deep coal mine, a theoretical mechanical model of shear slide block in the surrounding rock of deep coal roadway was established,the safety factor of shear slide block was deduced,and the failure mechanism of shear slide block was revealed. The mathematical model of the safety factor of shear slide block was derived by the limit equilibrium analysis method. It was concluded that under the condition of the inherent mechanical properties of the coal body,the cohesive force has the greatest influence on the shear slider safety coefficient of the coal body of the roadway gang with a positive linear relationship. In external conditions,the safety factor decreases exponentially with the increase of roadway height. Based on the shear slider theory model,taking the deep coal roadway in the Chengjiao coal mine as the research background, the UDEC software was used to analyze the influence of roadway height, cohesive force, joint and fracture, and support mode on shear slide block motion. The results show that:① The conjugate shear surface appears after mining on both sides of roadway,forming shear slide block motion. The higher the roadway height,the smaller the cohesion,and the more unstable the roadway. ② For joints development roadway,the damage of the hanging wall is larger than that of the footwall. The larger the dip angle,the greater the bulge of the roadway side. When the joint dip angle is 65°,the displacement of the shear sliding block in the side reaches 0.78 m. The middle and lower part of the crack is open,and it is easy to shear the bolt when using the bolt support,resulting in the bolt failure. ③ After the side cable is used,the crack opening is effectively restrained and the anchoring effect of the bolt is played normally. Compared with the support with ordinary anchor cable and without support,the protrusion of the side wall with cracks is only 0.14 m,which is reduced by 83.1% and 75.4% respectively. It is proved that adding cable anchor cable has a better control effect on the wall rock of the side wall. In view of the field situation and combined with the shear slider model,a collaborative control strategy of "crack prevention-clearance reduction-slip prevention" was proposed. i. e. the surface layer and shallow part are supported by using high strength pre-stressed anchor rod,anchor cable and metal net component reinforcement to prevent the crack of surrounding rock,the deep part is supported by using wall rock modification technology to reduce cracks,and the local serious instability part is supported by side cable to suppress shear sliding block movement. In the fractured surrounding rock of coal roadway,it forms a composite bearing structure,which effectively control the deep coal roadway surrounding rock deformation. The research results provide beneficial reference for the stability control of surrounding rock of deep coal roadway.

     

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