大倾角厚煤层巷道断面优化及变形控制技术研究

    Research on section optimization and deformation control technology of thick coal seam roadway with large inclination angle

    • 摘要: 针对大倾角煤层巷道围岩变形控制难题,以老石旦煤矿采区主运联巷为研究背景,分析了矿井地应力分布规律及巷道变形破坏特征,建立了不同巷道断面形状的数值模型,分析了不同断面巷道围岩应力、位移及塑性区分布特征,得出了老石旦煤矿大倾角煤层巷道最优断面,通过计算巷道顶板与巷帮载荷得出了巷道锚杆(索)支护技术参数,制定了巷道支护技术方案并开展了井下应用。研究结果表明:老石旦煤矿最大水平主应力与主运联巷夹角为46°~61°,夹角大不利于大倾角岩层稳定,造成大倾角岩层呈现剪切滑移破坏特征,数值模拟得出不同断面巷道均呈现不同程度的应力集中,直墙拱形断面和三心拱形断面优于矩形断面和梯形断面,直墙拱形断面巷道围岩应力分布相对均匀,塑性区分布范围及位移变化均优于三心拱形断面巷道,确定了直墙拱形断面为老石旦煤矿大倾角煤层巷道最佳断面。提高大倾角岩层围岩稳定性是控制围岩变形的关键,基于此,提出了高预应力锚杆支护抑制大倾角岩层滑移控制技术,采用理论计算与现场实测得出了锚杆(索)支护关键技术参数。井下应用效果表明,监测期内锚杆受力30 d后趋于稳定,锚杆(索)受力变化小,两帮最大变形33.4 mm,顶底板最大变形45.1 mm,巷道围岩表面位移明显减小,取得了大倾角煤层巷道变形控制效果。

       

      Abstract: In response to the difficulty of controlling the deformation of surrounding rock in coal seam roadways with large inclination angle, taking the main transportation roadway of Laoshidan Coal Mine as the research background, the distribution law of mine stress and the deformation and failure characteristics of roadways are analyzed. Numerical models of different roadway section shapes are established, and the distribution characteristics of surrounding rock stress, displacement, and plastic zone of roadways with different sections are analyzed. The optimal section of Laoshidan Coal Mine coal seam roadways with large inclination angle is obtained. The technical parameters of roadway anchor bolt and cable support are obtained by calculating the load on the roof and side of the roadway. A roadway support technology scheme is formulated and applied underground. The results show that the maximum horizontal principal stress in Laoshidan Coal Mine is at an angle of 46°-61° with the main transportation roadway. A large angle is not conducive to the stability of steeply inclined rock layers, resulting in shear slip failure characteristics of steeply inclined rock layers. Numerical simulations show that different sections of roadway exhibit varying degrees of stress concentration, with straight wall arch and three center arch sections being better than rectangular and trapezoidal sections. The stress distribution of the surrounding rock in the straight wall arch section roadway is relatively uniform, and the distribution range and displacement changes of the plastic zone are better than those in the three center arch roadway. The straight wall arch section is determined as the optimal section for coal seam roadway with large inclination angle in Laoshidan Coal Mine. Improving the stability of surrounding rock in steeply dipping rock layers is the key to controlling rock deformation. Based on this, a high prestressed anchor bolt support technology is proposed to suppress the sliding control of steeply dipping rock layers. The key technical parameters of anchor bolt and cable support are obtained through theoretical calculations and on-site measurements. The underground application effect shows that the anchor bolt and cable tends to stabilize after being subjected to force for 30 days during the monitoring period, with little change in the force of the anchor bolt and cable. The maximum deformation of the two sides is 33.4 mm, and the maximum deformation of the roof and floor is 45.1 mm. The displacement of the surrounding rock surface of the roadway is significantly reduced, and the deformation control effect of the coal seam roadway with large inclination angle is achieved.

       

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