大倾角伪俯斜工作面下端头支护阻力研究

Research on support resistance of head T-junction of pitching oblique working face in steeply dipping seam

大倾角走向长壁伪俯斜工作面顶板破断具有不同于真倾斜工作面的时序性和分区性,其顶板垮落充填特征极大影响了下端头支护安全性,需要针对下端头进行支护优化。采用数值计算、物理相似模拟实验、理论分析等综合方法,结合多个大倾角伪俯斜工作面实验与现场经验,分析了大倾角伪俯斜工作面顶板垮落充填规律和下端头顶板结构形成特征,建立了下端头三角板力学模型,提出了端头支架支护阻力计算公式。结果表明:大倾角伪俯斜工作面顶板垮落、滑移、充填交错发生,对采空区下部充填具有不均匀性,基本顶破断呈“U-X-O”动态演化过程,工作面下端头形成梯阶弧形三角板结构,弧形三角板传递至端头支架的载荷呈二次函数曲线分布,得到了下端头无充填时端头支架所需工作阻力计算公式。通过枣泉煤矿大倾角综放开采工程应用,确定了端头支架最小工作阻力为8 091.866 kN,选取ZTHJ11400/15.5/25型横式端头支架,保证了端头顶板结构的动态稳定,减少了端头漏冒事故,取得了良好支护效果。

The roof fracture of pitching oblique longwall face is different from that of steeply inclined working face in terms of timing and zoning.and its collapse and filling characteristics greatly affect the safety of head T-junction support, which needs to be optimized.Such methods as numerical simulation, physical similarity simulation experiment, and theoretical analysis are adopted, and based on the multiple experiments and project experience of pitching oblique longwall face, the law of roof collapse and filling and the formation characteristics of the roof structure at head T-junction of pitching oblique longwall face are analyzed.The triangular plate mechanical model of head T-junction is established, and calculation formula of the support resistance of the end support is deduced.The results shows that roof caving, slipping and filling of pitching oblique longwall face occur staggeredly, causing a non-uniform filling of goaf near head T-junction.The “U-X-O” dynamic evolution process of main roof fracture is showed, the stepped arc-triangular plate structure of head T-junction is formed, the load transmitted by the arc-triangular plate to the end support is distributed in a quadratic function curve, and the calculation formula for working resistance of head T-junction with no filling is obtained.Through the application of the fully mechanized caving mining project at Zaoquan coal mine, the minimum working resistance of end support is determined to be 8 091.866 kN,and the ZTHJ11400/15.5/25 type horizontal end support is selected to ensure the dynamic stability of roof structure in head T-junction, and the leakage accident of head T-junction is reduced, and a good supporting effect is achieved.