地铁隧道浅埋暗挖施工对既有桥桩的影响分析

发布时间：2018-04-20 04:29

本文选题：地铁隧道 + 浅埋暗挖法　；参考：《西安科技大学》2015年硕士论文

【摘要】：近年来,我国城市发展快速,地面交通拥堵严重,人们也越来越重视地下空间资源的利用,各大中城市为缓解地面交通压力而进行地下轨道交通建设。地铁隧道施工受地面和地下环境的限制较大,在穿越既有建筑物基础附近时会导致基础周围土体发生位移,进而使得桩基产生附加内力和变形,导致上部结构出现整体或不均匀沉降,从而危及桥梁和建筑物的安全使用。因此,研究地铁浅埋暗挖法施工对既有桩基础的影响,对工程施工具有重要的借鉴意义。本文对前人的研究成果进行了总结,在此基础上分析了隧道开挖与桩基位移、轴力及桩周摩阻力变化之间的关系,主要进行的工作有以下几个方面:(1)分析了隧道开挖引起的土体位移变化和主要影响因素,采用Loganathan解析公式计算隧道开挖引起的土体位移;分析了土体竖向位移对既有桥桩的影响规律,然后通过剪切位移法建立起单桩及群桩位移控制方程,求解方程得出桩身位移及轴力变化的表达式;建立起隧道开挖前桩身的位移控制方程,得出开挖前的桩身位移、轴力分布表达式。(2)基于所推导的桩身位移及轴力公式,将其应用到具体的工程实例中,计算了隧道开挖前的单桩及群桩位移轴力分布;将开挖引起的土体竖向位移分布进行多项式拟合,计算出隧道开挖引起的单桩及群桩变形和受力变化;最后对单桩进行了参数分析。(3)通过对施工现场进行监测,获取数据并分析得出地表和桥桩沉降规律;利用FLAC3D有限差分软件建立模型,就实际采用环形开挖预留核心土法引起的土体桥桩沉降进行数值计算,得出其分布规律;将所得的计算、实测及模拟结果进行对比,通过实际监测和模拟结果验证计算的正确性。(4)对现行规范中桥桩变形的控制标准进行了总结;根据计算的结果确定其加固的范围;提出了实际工程中控制桥桩变形的措施,可以给工程施工进行指导并具有一定的参考意义。
[Abstract]:In recent years, the urban development of our country is fast, the ground traffic congestion is serious, people pay more and more attention to the utilization of the underground space resources, each big and medium city carries on the underground rail transit construction in order to alleviate the ground traffic pressure. The construction of subway tunnel is restricted by the ground and underground environment, which will lead to the displacement of the soil around the foundation when passing through the existing building foundation, and then cause the additional internal force and deformation of the pile foundation. Causes the superstructure to appear the integral or uneven settlement, thus endangers the bridge and the building safe use. Therefore, it is of great significance for engineering construction to study the influence of shallow underground excavation on the existing pile foundation. In this paper, the previous research results are summarized, and the relationship between tunnel excavation and pile foundation displacement, axial force and friction around pile is analyzed. The main work is as follows: (1) analyzing the displacement of soil caused by tunnel excavation and the main influencing factors, using Loganathan analytic formula to calculate the displacement of soil caused by tunnel excavation; The influence of soil vertical displacement on existing bridge piles is analyzed, and then the displacement control equations of single pile and group pile are established by shear displacement method, and the expressions of pile displacement and axial force are obtained by solving the equations. The displacement control equation of pile body before excavation is established, and the displacement of pile body before excavation is obtained. The expression of axial force distribution is obtained. Based on the derived formula of displacement and axial force of pile body, it is applied to concrete engineering examples. The axial force distribution of single pile and group pile before tunnel excavation is calculated and the deformation and force change of single pile and group pile caused by tunnel excavation are calculated by polynomial fitting of vertical displacement distribution of soil caused by excavation. Finally, the parameters of the single pile are analyzed. 3) by monitoring the construction site, obtaining the data and analyzing the settlement law of the ground and bridge pile, the model is established by using the FLAC3D finite difference software. The settlement of soil bridge pile caused by ring excavation with reserved core soil method is numerically calculated, and its distribution law is obtained, and the calculated, measured and simulated results are compared. Through the actual monitoring and simulation results to verify the correctness of the calculation. 4) the control standard of bridge pile deformation in the current code is summarized, the reinforcement range is determined according to the calculation results, and the measures to control the bridge pile deformation in practical engineering are put forward. It can guide the project construction and has certain reference significance.
【学位授予单位】：西安科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U231.3;U456.3

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