地铁盾构施工对桩锚支护结构影响研究

发布时间：2018-01-07 03:12

本文关键词：地铁盾构施工对桩锚支护结构影响研究　出处：《郑州大学》2016年硕士论文　论文类型：学位论文

【摘要】：随着城市快速发展,建筑市政道路和铁道工程交相呼应,在彼临的整体建设格局下,往往会出现多种工法交叉施工的现象,其中就包括地铁隧道近穿基坑支护工程的情况。盾构施工会对邻近的桩锚支护结构造成影响,桩后土体会产生向基坑内的位移,导致支护桩侧移的增大和锚杆轴力的减小,影响基坑工程的安全性与稳定性。本文运用三维有限元模型并结合现场试验,对盾构施工对邻近桩锚支护结构的影响进行了系统的分析,并得到了一些结论。本文的主要内容和研究成果如下:(1)依托郑州建业凯旋广场基坑支护工程现场条件及郑州地铁2号线盾构施工工况,建立了地铁盾构施工近穿在用桩锚支护结构的三维有限元数值分析模型,模拟研究了盾构施工对桩锚支护结构受力变形分布规律的影响;(2)采用有限元方法数值模拟分析了盾构隧道相对于既有在用桩锚支护结构的空间位置发生变化时,盾构施工对支护结构受力变形的影响规律,结果表明:在一定范围内桩后土体地表沉降量和支护桩侧移量都随隧道与支护桩水平距离的增大而减小,隧道位于锚杆锚固段正下方时,锚杆的轴力损失率最大;隧道上覆土体越厚时,盾构施工引起桩后土体的沉降量越小,支护桩的侧移和锚杆轴力的损失也越小;(3)现场监测了地铁盾构施工近距离穿过在用桩锚支护结构时,既有支护结构的变形和受力变化情况,并与数值模拟成果进行了对比分析。在此基础上,提出了消除或减轻地铁隧道盾构推进过程对桩锚支护结构安全性及稳定性不利影响的合理建议,为以后类似工程情况提供了理论参考。
[Abstract]:With the rapid development of the city, the construction of municipal roads and railway projects echo each other, in the face of the overall construction pattern, there are often a variety of construction methods of cross-construction phenomenon. The shield construction will affect the adjacent pile-anchor support structure and the displacement of the soil behind the pile to the foundation pit. As a result of increasing the lateral displacement of supporting pile and decreasing the axial force of bolt, the safety and stability of foundation pit engineering are affected. In this paper, three dimensional finite element model is used and combined with field test. The influence of shield construction on the supporting structure of adjacent piles and anchors is analyzed systematically. Some conclusions are obtained. The main contents and research results of this paper are as follows: 1) relying on the site conditions of foundation pit support project of Zhengzhou Jianye Triumph Square and the construction conditions of shield tunneling of Zhengzhou Metro Line 2. The three-dimensional finite element numerical analysis model of the pile-anchor supporting structure in the shield construction of subway is established, and the influence of shield construction on the stress and deformation distribution of the pile-anchor supporting structure is simulated. 2) numerical simulation of shield tunnel with finite element method is used to analyze the influence of shield construction on the deformation of supporting structure when the space position of shield tunnel is changed relative to the existing pile-anchor supporting structure. The results show that the amount of soil surface settlement and the lateral displacement of the supporting pile decrease with the increase of horizontal distance between the tunnel and the supporting pile in a certain range, and the tunnel is located directly below the bolt anchoring section. The axial force loss rate of anchor rod is the largest; When the overlying soil is thicker, the settlement of the soil after shield construction is smaller, the lateral displacement of the supporting pile and the loss of the axial force of the anchor are also smaller. (3) the deformation and stress change of the existing supporting structure are monitored when the shield tunneling is passing through the supporting structure with pile and anchor at close range, and the results are compared with the numerical simulation results. Reasonable suggestions are put forward to eliminate or mitigate the adverse effects of shield tunneling on the safety and stability of pile-anchor supporting structure, which provides a theoretical 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】：2016
【分类号】：U455.43;U231.3

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