土压平衡盾构掘进对上软下硬地层扰动研究

发布时间：2018-01-10 01:08

本文关键词：土压平衡盾构掘进对上软下硬地层扰动研究　出处：《岩石力学与工程学报》2017年04期 　论文类型：期刊论文

【摘要】：采用Ф800 mm模型盾构开展室内掘进试验以研究土压盾构掘进对上软下硬地层的扰动特征,试验充分考虑土压盾构动态施工全过程的影响。建立与室内掘进试验对应的离散元模型定量分析软土超挖现象并挖掘其他地层扰动信息。研究结果表明:土压盾构在硬岩地层中掘进时地表沉降曲面呈现向软土侧展开的"扇面"状;进入上软下硬地层后地表沉降值与范围均急剧增加,沉降曲面呈现自上而下逐渐收缩的"漏斗"状,硬岩侧收缩速度快于软土侧;上软下硬地层地表位移小于均质软土地层,而地中沉降显著大于后者;上软下硬地层地中沉降槽宽度参数沿深度方向呈指数增加,硬岩占断面比例越小,地中沉降槽宽度参数越大。相同埋深条件下,上软下硬地层地中沉降槽宽度参数小于均质软土地层。硬岩占断面比例越大,渣土中砂土所占比例与相应理论值差异越明显。地表水平位移在竖向沉降槽曲线反弯点处最大。研究可为土压盾构在上软下硬地层施工提供参考。
[Abstract]:In order to study the disturbance characteristics of the earth pressure shield tunneling on the upper soft and hard ground, the indoor tunneling test was carried out by using the 800 mm shield tunneling model. The effect of dynamic construction of earth pressure shield is taken into account in the test. The discrete element model corresponding to the indoor tunneling test is established to quantitatively analyze the phenomenon of soft soil overdigging and to excavate the information of other strata disturbance. The results show that:. When the earth pressure shield tunneling in the hard rock stratum, the surface subsidence surface presents the "sector" shape which extends to the soft soil side; After entering the upper soft and hard strata, the surface subsidence value and range increase sharply, the subsidence surface presents the "funnel" shape of gradually shrinking from the top to the bottom, and the contraction speed of the hard rock side is faster than that of the soft soil side. The surface displacement of upper soft and lower hard strata is less than that of homogeneous soft soil, and the settlement in the ground is significantly larger than that of the latter. The width parameter of subsidence trough increases exponentially along the depth direction. The smaller the ratio of hard rock to the section, the larger the width parameter of subsidence trough in the ground. The width parameter of subsidence trough in upper soft and lower hard stratum is smaller than that in homogeneous soft soil. The ratio of hard rock to cross section is larger. The difference between the proportion of sand and the corresponding theoretical value is more obvious. The horizontal displacement of the earth surface is the largest at the reverse bending point of the vertical settlement trough curve. The study can provide a reference for the construction of the earth pressure shield in the upper soft and hard ground.
【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】：国家科技支撑计划(2013BAB10B02,2013BAB10B04) 2014年度西南交通大学博士研究生创新基金资助项目~~
【分类号】：U455.43
【正文快照】： 盾构法以安全、快速、对周围环境影响小等优点,在城市轨道交通建设领域得到了广泛运用。我国幅员辽阔,地质条件复杂多变,盾构隧道穿越地层的工程力学性质往往是影响施工成败的关键因素。上软下硬地层是我国广州、深圳、福州等地区地铁建设中遇到的一种典型地质条件,具有岩土体

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