异形巷道空顶区围岩稳定性及关键影响因素分析

    Analysis of surrounding rock stability and key influencing factors in the goaf area of special-shaped roadway

    • 摘要: 针对某矿5煤层异形回采巷道,基于薄板理论得到异形巷道空顶距计算公式,分析了不同因素对空顶距的影响规律及权重,并采用FLAC3D数值模拟分析了不同因素对空顶区围岩变形特征及垂直应力分布的影响规律。研究结果表明:空顶区顶板的稳定性与抗拉强度、巷道半宽、顶板厚度、顶板倾斜角度、侧压系数及埋深有关,其中巷道宽度及薄板厚度是关键影响因素;根据5煤层地质条件,确定异型巷道的理论最大空顶距为3.653 m,考虑安全系数实际最大空顶距不超过3 m;数值模拟确定合理的支护强度及与巷道方向一致的最大水平应力分布方位,可为快速掘进提供有利条件。在3X51S掘进工作面进行现场应用,空顶距离达到2~3 m,一定程度上提高了掘进速度,且巷道稳定后最大位移不超100 mm,表明应用效果较好。

       

      Abstract: Aiming at the special-shaped mining roadway of No.5 coal seam in coal mine, the calculation formula of the empty roof distance of the special-shaped roadway is obtained based on the thin plate theory, the influence law and weight of different factors on the empty roof distance are analyzed, and the influence law of the key factors on the deformation characteristics of the surrounding rock and the vertical stress distribution in the empty roof area is analyzed by FLAC3D numerical simulation.The results show that the stability of the roof in the goaf area is related to the roadway width, vault height, tensile strength and roof load, among which the roadway width and sheet thickness are the key factors.The theoretical maximum empty roof distance of special-shaped roadway is determined to be 3.653 m, and the actual maximum empty roof distance is 3 m after considering the safety factor.Numerical simulation to determine the reasonable support strength and the maximum horizontal stress distribution direction consistent with the roadway direction can provide favorable conditions for rapid tunneling.In the field application of 3X51S heading working face, the empty roof distance reaches about 2-3 m, which improves the excavation speed, and the maximum displacement after the roadway is stable does not exceed 100 mm.

       

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