焦煤一矿坚硬岩层下切顶护巷关键参数研究

    Study on key parameters of roof cutting and roadway protection under hard rock stratum in No.1 Coking Coal Mine

    • 摘要: 以焦煤一矿8311综采工作面切顶护巷工程为研究对象,针对直接顶含厚层坚硬砂岩条件下的预裂爆破切顶关键参数展开研究。构建了双孔爆破动力学模型,运用连续-离散元耦合数值模拟方法,对比研究了不同切顶参数组合对巷道围岩形变规律的影响。研究表明:切顶技术能缩短巷道顶板悬臂结构长度,达到应力释放与巷道防护的双重效果;切顶高度参数调整主要控制采空区矸石充填密实度与悬臂岩梁厚度,而切顶角度变化则主导悬臂结构长度及矸石对顶板的侧向约束效应,二者均存在最优阈值而非线性正相关。经工程验证,当切顶高度取8.5 m、切顶角度设定为15°、爆破孔距调整为750 mm时,巷道围岩稳定性得到有效控制,成功实现了沿空留巷技术目标。

       

      Abstract: Taking the roof cutting and roadway protection project of 8311 fully mechanized mining face in No.1 Coking Coal Mine as the research object, the key parameters of pre-splitting blasting roof cutting under the condition of direct roof containing thick hard sandstone are studied. The dynamic model of double-hole blasting was constructed, and the continuous-discrete element coupling numerical simulation method was used to compare and study the influence of different roof cutting parameter combinations on the deformation law of roadway surrounding rock. The research shows that the roof cutting technology can shorten the length of the cantilever structure of the roadway roof and achieve the dual effects of stress release and roadway protection. The adjustment of roof cutting height parameter mainly controls the filling density of gangue in goaf and the thickness of cantilever rock beam, while the change of roof cutting angle dominates the length of cantilever structure and the lateral restraint effect of gangue on roof. Both of them have optimal threshold and nonlinear positive correlation. It is verified by engineering that when the roof cutting height is 8.5 m, the roof cutting angle is set to 25°, and the blasting hole spacing is adjusted to 750 mm, the stability of roadway surrounding rock is effectively controlled, and the technical goal of gob-side entry retaining is successfully realized.

       

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