公路隧道下穿倾斜煤层采空区室内开挖模型试验

发布时间：2018-01-06 16:11

本文关键词：公路隧道下穿倾斜煤层采空区室内开挖模型试验　出处：《地下空间与工程学报》2017年04期 　论文类型：期刊论文

【摘要】：开展了公路隧道下穿倾斜煤层采空区室内相似模型试验,考虑了不同开挖进尺和初期支护参数的影响,通过埋设位移计、土压力盒及电阻应变片,测量了隧道开挖过程中采空区附近地层的移动和初期支护的内力。试验结果表明,增大隧道开挖进尺,地层最终沉降量、隧道施工过程中的沉降速率均显著增加,沉降槽变得更窄、更陡。减少钢拱架数量也会引起地层沉降的增加,但增加幅度相对较小。增加开挖进尺或减少钢拱架数量还将引起钢拱架弯矩增加,使得拱部最大弯矩向右侧移动,并改变轴力分布,降低初支结构稳定性。研究结果表明,隧道下穿倾斜煤层采空区地层时,可以不对采空区进行加固,但需要降低围岩级别进行初期支护设计,并采用较短的循环进尺进行隧道开挖,同时缩短上台阶初期支护时间,尽早使初期支护闭合成环,从而降低开挖引起的地层的沉降,保证初期支护结构的稳定性。
[Abstract]:The indoor similar model test of goaf in the goaf of inclined coal seam under highway tunnel is carried out, considering the influence of different excavation advance and initial support parameters, through the installation of displacement meter, earth pressure box and resistance strain gauge. The movement of the strata near the goaf and the internal force of the initial support are measured during the excavation of the tunnel. The experimental results show that the final settlement of the stratum is increased by increasing the excavation advance of the tunnel. During the tunnel construction, the settlement rate increases significantly, and the settlement trough becomes narrower and steeper. Reducing the number of steel arches will also cause the increase of ground settlement. But the increase is relatively small. Increasing the excavation ruler or reducing the number of steel arches will also cause the increase of bending moment of steel arch, make the maximum moment of arch move to the right, and change the distribution of axial force. The research results show that the goaf can not be strengthened when the tunnel passes through the goaf of inclined coal seam, but the initial support design is needed to reduce the surrounding rock level. At the same time, it can shorten the initial support time and make the initial support close to the ring as soon as possible, so as to reduce the settlement of the stratum caused by excavation. To ensure the stability of the initial support structure.
【作者单位】：西南交通大学交通隧道工程教育部重点实验室;云南省交通规划设计研究院;
【基金】：国家自然科学基金(51278422) 国家科技支撑计划课题(2012BAG05B03) 四川省青年科技基金(2012JQ0021) 中央高校基本科研业务费专项资金(SWJTU11ZT33)
【分类号】：U456
【正文快照】： 0引言采空区是煤矿工作面开采后形成的塌落空间,地下采空区空间分布特征规律性差、隐伏性强。隧道穿越煤层采空区施工将对围岩产生扰动从而打破现有的平衡状态,“活化”既有采空区。采空区从下到上可以划分为3个不同的区带:冒落带、导水裂隙带和弯曲沉降带[1]。如果勘察期间探

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