隧道掌子面前方小型有压溶腔对围岩稳定性影响分析

发布时间：2018-01-13 09:21

本文关键词：隧道掌子面前方小型有压溶腔对围岩稳定性影响分析　出处：《湖南大学学报(自然科学版)》2017年09期 　论文类型：期刊论文

【摘要】：以重庆双碑隧道工程为研究对象,采用FLAC3D模拟施工中掌子面正前方存在小型带压溶腔的情况,根据计算所得安全临界距离,采用自主发明的一套模拟溶腔内压的试验装置,开展了几何相似比为1∶25的室内模型开挖试验,研究隧道开挖至安全临界距离时,溶腔内压增加至掌子面崩坏过程中,此阶段掌子面周边围岩压力、掌子面位移以及初期支护内力的变化规律.结果表明:随着掌子面前方溶腔内压的增加,掌子面位移先呈近似正比例增加,随后掌子面位移增大速率逐渐增加,最后产生突变破坏;围岩压力随溶腔内压增大呈现出增大趋势,其中拱顶处围岩压力影响较大,拱肩与仰拱处次之,其他位置围岩压力影响不大;钢拱架弯矩分布规律在不同溶腔内压作用下基本相同,在溶腔内压增大过程中,初期支护拱顶以及仰拱处弯矩呈增大趋势,其影响主要集中在拱顶附近及拱底处,其它位置处弯矩影响不大;随溶腔内压增大钢拱架轴力均呈现增大趋势,轴力变化较大位置主要出现在拱顶处,左右拱腰处次之,仰拱以及拱肩处变化幅度较小;受溶腔内压大小的影响,掌子面处位移、初支内力以及偏心距变化速率均越来越快.
[Abstract]:Chongqing Shuangbei tunnel project as the research object, using FLAC3D to simulate the construction in the face just ahead of the situation with pressure cavity small, according to the calculated critical distance, invented by a simulation test device for cavity pressure solution, the geometric similarity ratio of 1 to 25 of the indoor model test of excavation. Study on tunnel excavation to the critical distance, the solution cavity pressure increases to the tunnel face collapse process, surrounding rock pressure of tunnel face in this stage, the displacement and initial support force changes. The results show that with the front of the face cavities pressure increases, the face displacement is approximately proportional to increase, then the face displacement increase rate increases gradually, finally produced mutation failure; rock pressure with solution cavity pressure increasing, the pressure of the surrounding rock at the crown influence, spandrel and arch at the time The other position has little effect on the surrounding rock pressure; steel arch bending moment distribution is similar in different cavities under pressure, in the solution cavity pressure increases during the initial support of vault and invert the bending moment increases, its influence is mainly concentrated in the Vault near the bottom and arch at the moment, other locations have little impact; with the solution cavity pressure increases the axial force of steel arch were increased, the axial force variation position occurred mainly in the vault, left and right at the haunches of arch and spandrel of smaller amplitude; by the influence of solution cavity pressure, face displacement, internal force and initial eccentricity changes rate more and more quickly.

【作者单位】：西南交通大学交通隧道工程教育部重点实验室;
【基金】：国家自然科学基金资助项目(51278422,51578460) 国家科技支撑计划项目(2012BAG05B03) 四川省青年科技基金资助项目(2012JQ0021)~~
【分类号】：U451.2
【正文快照】： 随着中国铁路网不断发展完善,在西南山区诸多长大复杂岩溶隧道正在修建或即将修建[1],在隧道施工中很容易遇到掌子面前方存在小型带压溶腔的情况.由于岩溶的复杂性、发育的不规律性,隧道在此类地层中修建具有较高的风险[2].虽然目前对于掌子面前方小型溶洞的提前预报已经具有

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