粉土地区基坑开挖对下卧地铁隧道变形影响研究

发布时间：2018-04-09 04:12

本文选题：隧道变形　切入点：基坑工程　出处：《郑州大学》2017年硕士论文

【摘要】：随着城市交通的快速发展,地下交通线路与既有地铁隧道交叉影响问题逐渐凸显,特别是地下交通工程采用明挖施工上跨运营地铁隧道时隧道的变形控制问题。基坑开挖卸荷土体发生回弹,会引起下卧运营地铁隧道发生竖向隆起变形,对地铁运营的安全和稳定产生威胁。本文基于郑州东区粉土的压缩-回弹力学特性,采用三维数值模拟的方法,对基坑开挖时下卧地铁隧道的变形特性进行了系统的研究。主要研究内容如下:(1)现场取土进行室内土工试验,并得出郑州东区粉土土样修正剑桥模型主要参数临界状态有效应力比M=1.414、塑性对数体积模量λ=0.0662和弹性对数体积模量κ=0.0021。(2)采用数值模拟方法研究了基坑开挖对下卧地铁隧道的变形影响,并进行理论分析,理论计算与数值模拟结果吻合度较高。(3)分别对基坑深度、隧道与坑底距离、土体参数变化时基坑开挖引起下卧地铁隧道的变形规律进行了研究。并对分块开挖及时堆载和施加抗拔桩墙这两种加固措施对隧道变形控制效果进行了分析。研究结果表明:隧道最大竖向位移随基坑开挖深度的增加逐渐增大但增加幅度逐渐变小;隧道最大竖向位移随与坑底距离的增大逐渐减小并趋于平缓;采取基坑分块开挖措施可以减小隧道最大竖向位移约10%,隧道位移减小量与堆载量呈线性关系;隧道竖向位移随抗拔桩墙长度的增加而减小,随抗拔桩墙宽度的增加而减小;抗拔桩墙厚度对隧道位移的控制影响不大;隧道竖向位移随与抗拔桩墙水平距离的增加而增加,当距离大于1倍隧道直径时抗拔桩墙基本不再起作用。本文提出分块开挖及时堆载以及施加抗拔桩墙的综合措施来控制隧道位移变形,效果显著,为今后类似工程提供参考。
[Abstract]:With the rapid development of urban traffic, the cross influence of underground traffic lines and existing subway tunnels is becoming more and more prominent, especially the deformation control problem of underground traffic engineering.The springback of unloading soil in foundation pit excavation will cause vertical uplift deformation of underground tunnel which will threaten the safety and stability of subway operation.Based on the compression-springback mechanical properties of silt in the eastern part of Zhengzhou, the deformation characteristics of underground tunnel during excavation are studied systematically by using three-dimensional numerical simulation method in this paper.The main contents of the study are as follows: (1) taking soil from the site for indoor geotechnical tests,The effective stress ratio of critical state (M1.414), the plastic logarithmic volume modulus 位 (0.0662) and the elastic logarithmic volume modulus 魏 (0.0021.m2) of the modified Cambridge model of silty soil samples in the eastern part of Zhengzhou are obtained. The numerical simulation method is used to study the excavation of foundation pit to the underground subway.The influence of tunnel deformation,The theoretical analysis shows that the theoretical calculation and numerical simulation results are in good agreement with each other. The deformation law of underground tunnel caused by foundation pit excavation is studied respectively when the depth of foundation pit, the distance between tunnel and pit bottom, and the soil parameters change.The control effect of tunnel deformation is analyzed by the two reinforcement measures, namely, timely heaped excavation in block excavation and the application of anti-drawing pile wall.The results show that the maximum vertical displacement of the tunnel increases gradually with the increase of excavation depth, and the maximum vertical displacement decreases gradually with the increase of the distance between the tunnel and the bottom of the pit.The maximum vertical displacement of the tunnel can be reduced by about 10 percent and the tunnel displacement decreases linearly with the pile load, the vertical displacement of the tunnel decreases with the increase of the length of the pile wall and the width of the pile wall.The vertical displacement of the tunnel increases with the increase of the horizontal distance between the pile wall and the uplift pile wall, and when the distance is more than 1 times the diameter of the tunnel, the anti-pulling pile wall has no effect on the control of the displacement of the tunnel, and the vertical displacement of the tunnel increases with the increase of the horizontal distance between the wall and the wall.This paper puts forward the comprehensive measures to control the displacement and deformation of the tunnel by using block excavation timely heaped load and the application of anti-drawing pile wall. The effect is remarkable and provides a reference for similar projects in the future.
【学位授予单位】：郑州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU753;U456.3;U231

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