深井6.8 m大采高大断面沿空掘巷窄煤柱宽度及围岩控制研究

    Study on narrow coal pillar width and surrounding rock control of gob-side entry driving with large mining height and section of 6.8 m in deep coal mine

    • 摘要: 为解决深部大采高大断面沿空掘巷围岩裂隙恶性发育、采掘扰动剧烈、窄煤柱弱承载以及巷道支护系统破损失效等难题,以大海则煤矿20203工作面回风巷小煤柱掘巷为工程背景,运用内外应力场及极限平衡理论、数值计算模拟、工程实践等方法,综合确定深井6.8 m大采高大断面沿空掘巷窄煤柱合理宽度为6.5 m,并针对性地提出了“高强度混凝土铺底+巷帮高预应力锚杆支护+顶板柔性锚杆强支护撑顶+菱形金属网护巷”的围岩综合化控制技术。研究表明:该地质条件下内应力场宽度为14.4 m,上工作面回采后煤柱破碎区宽度为3.1 m,窄煤柱合理宽度范围为5.8~8.2 m;6.5~9.5 m煤柱尺寸时,煤柱受力得到改良,煤柱上方及巷道顶板出现弹性核区,能较大程度地发挥锚杆(索)锚固效果以保证顶帮稳定;支护完成32 d后巷道收敛变形趋于稳定,实体煤帮、煤柱帮、实体煤侧顶板及煤柱侧顶板最大变形量分别为52、60、62、67 mm,巷道整体变形处于可控范围,6.5 m窄煤柱和围岩强力综合化控制技术可实现深井大采高大断面沿空掘巷窄煤柱稳定承载及围岩长期有效控制。

       

      Abstract: In order to solve the problems of vicious development of surrounding rock fissures, severe mining disturbance, weak bearing capacity of narrow coal pillar and damage and failure of roadway support system of gob-side entry driving with large section of large mining height in deep coal mine, taking the small coal pillar roadway excavation of 20203 working face of Dahaize Coal Mine as the engineering background, the internal and external stress field, limit equilibrium theory, numerical calculation simulation, engineering practice are used. It is comprehensively determined that the reasonable width of narrow coal pillar of gob-side entry driving with large section of 6.8 m mining height in deep coal mine is 6.5 m, and the surrounding rock comprehensive control technology of “high-strength concrete bedding + high prestressed bolt support of roadway sides + roof flexible bolt strong support + diamond metal mesh” is proposed. The research shows that: the width of internal stress field under this geological condition is 14.4 m, the width of coal pillar crushing area after mining previous working face is 3.1 m, and the reasonable width range of narrow coal pillar is 5.8 to 8.2 m; when the coal pillar size is 6.5 to 9.5 m, the stress of the coal pillar is improved, and the elastic zone appears above the coal pillar and the roadway roof, which can give full play to the anchoring effect of bolt (cable) to ensure the stability of the roof and sides; the convergence deformation of the roadway tends to be stable 32 days after the support is completed. The maximum deformation of the solid coal wall, coal pillar wall, solid coal side roof and coal pillar side roof are 52 mm, 60 mm, 62 mm and 67 mm respectively. During the mining of this working face, the overall deformation of the roadway is in a controllable range. The 6.5 m narrow coal pillar and comprehensive control technology of surrounding rock can realize the stable bearing of narrow coal pillar and long-term effective control of surrounding rock of gob-side driving with large section of large mining height in deep coal mine.

       

    /

    返回文章
    返回