综放工作面沿空开切眼跨度大、顶煤厚度大、沿空小煤柱、围岩松软、裂隙发育,支护难度大。针对宽度8 m、顶煤厚度5.6 m的综放沿空开切眼,采用理论分析、数值模拟、现场试验及监测分析等方法,研究了煤柱的留设原则、煤柱应力分布特征,优选了煤柱宽度;分析了综放沿空开切眼的支护机理,设计并试验了锚网带与锚索支护、锚网带与桁架锚索支护方案。研究结果表明,煤柱合理宽度为4~5m。2种支护方案改善了顶煤的受力状态,提高了围岩承载能力,有效控制了大跨度、厚顶煤的离层、裂隙扩展和弯曲下沉,保证了综放沿空开切眼的稳定性。
Open-off cut along gob area of fully mechanized caving face has the characteristics of large span, large thickness of top coal, small coal pillar along gob area, soft surrounding rock and fracture development, so, its support is difficult. In this paper, in view of the open-off cut along gob area with 8 m in width, and 5.6 m in thickness, by using theoretical analysis, numerical simulation, field test and monitoring analysis, the remaining principle of coal pillars and pillar stress distribution characteristics were studied, and the coal pillar width was optimized. In addition, the support mechanism of open-off cut along gob area was analyzed, and the supporting schemes including the anchor net belt combined with anchor cable, and the anchor net belt with truss and anchor rope were designed and tested. The re-sults show that the rational width of coal pillar is around 4-5 m, and the two supporting schemes of anchor net belt combined with anchor cable and truss and anchor rope, respectively, can improve the forced state of top coal and the bearing capacity of surrounding rock, effectively control the bed separa-tion, fracture propagation, bending and subsidence of large span and thick top coal, and ensure the sta-bility of open-off cut along gob area of fully mechanized caving face.