地铁隧道穿越城市异形板桥风险评估及主动防护研究

发布时间：2018-02-09 05:18

本文关键词： 地铁隧道穿越桩基异形板桥易损性指数风险评估雷达图法剩余承载力基础沉降控制顶升量控制关键顶升参数　出处：《北京交通大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着我国地下空间的开发与利用,城市地铁工程的建设正迎来新一轮高潮。考虑到城市建设的复杂性,地铁隧道穿越城市桥梁基础是不可避免的。作为城市桥梁系统中最为薄弱的部位,异形板桥的安全必须引起工程技术人员足够的重视。本文依托北京地铁7号线穿越广安门异形板桥工程,通过工前风险评估、异形板桥剩余承载力评定、异形板桥基础沉降控制标准的确定和主动顶升支护关键参数的优化等环节,实现盾构隧道穿越城市异形板桥工程的安全控制。本文提出的关于穿越工程风险定级和主动支护关键参数设计的方法在实际工程中得到了验证,可为今后隧道穿越异形板桥工程的风险评估和顶升支护设计提供参考。本文主要内容包括:(1)从盾构隧道施工对周围土层扰动的机理出发,研究了盾构隧道施工对单桩及群桩基础的影响,重点分析了群桩基础的遮拦效应和土拱效应,并使用FLAC3D软件对盾构隧道施工影响下邻近群桩的基础变形进行了数值模拟分析。(2)通过引入单向受压弹簧模拟橡胶支座的作用,对城市异形板桥的结构特点和沉降力学特性进行了有限元分析。引入易损性指数,实现了对异形板桥基础沉降易损性的评价。(3)在分析盾构施工对地层和桩基影响的基础上,引入了改进肯特法风险评估模型。通过结合工程实际状况并优化相关参数和评价指标,使用FLAC3D和Midas Civil进行数值模拟,从而实现了盾构隧道穿越广安门异形板工程的风险定级。(4)在分析广安门异形板桥力学特性的基础上,通过引入雷达图法实现了对异形板桥剩余承载力的评估。借助Midas Civil进行异形板桥的基础沉降特性分析,确定了广安门异形板桥单墩沉降控制标准,并在此基础上得到不同基础组合沉降的控制方法。(5)通过对异形板桥主动顶升过程中各种工况的有限元模拟,并借助前期对异形板桥承载力的折减分析,得到了广安门异形板桥顶升过程中各墩柱的顶升控制限值,进而实现了各墩位不同顶升量的组合顶升控制。(6)在使用有限元分析的基础上,通过对不同顶升工况下异形板内力响应结果的对比,得出了异形板桥顶升过程中的关键参数的最优取值,优化了异形板桥的主动顶升过程中的关键参数。
[Abstract]:With the development and utilization of underground space in China, the construction of urban subway project is facing a new wave of climax. Considering the complexity of urban construction, It is inevitable for subway tunnels to pass through the foundation of urban bridges. As the weakest part of the urban bridge system, The safety of special-shaped slab bridge must be paid enough attention by engineers and technicians. This paper relies on Beijing Metro Line 7 to pass through the Guang'anmen special-shaped slab bridge project. Through pre-construction risk assessment, the residual bearing capacity of special-shaped slab bridge is evaluated. The determination of settlement control standard for foundation of special-shaped slab bridge and the optimization of key parameters of active jacking support, The safety control of shield tunneling through urban special-shaped slab bridge is realized. The method of risk classification and design of key parameters of active support proposed in this paper has been verified in practical engineering. It can be used as a reference for risk assessment and jacking support design of tunnel crossing through special-shaped slab bridge in the future. The main contents of this paper include: 1) starting from the mechanism of shield tunnel construction disturbing the surrounding soil layer, The influence of shield tunnel construction on single pile and pile group foundation is studied, and the blocking effect and soil arch effect of pile group foundation are analyzed. The foundation deformation of adjacent piles under the influence of shield tunnel construction is simulated by using FLAC3D software. The structural characteristics and settlement mechanics characteristics of special shaped slab bridges in cities are analyzed by finite element method. The vulnerability index is introduced to evaluate the foundation settlement vulnerability of special-shaped slab bridges. On the basis of analyzing the influence of shield construction on stratum and pile foundation, An improved Kent method risk assessment model is introduced. By combining the actual engineering conditions and optimizing the relevant parameters and evaluation indexes, the FLAC3D and Midas Civil are used to carry out the numerical simulation. Thus, the risk grading of shield tunnel passing through Guang'anmen special-shaped plate engineering is realized. On the basis of analyzing the mechanical characteristics of Guang'anmen special-shaped slab bridge, the paper analyzes the mechanical characteristics of Guang'anmen special-shaped slab bridge. The residual bearing capacity of special-shaped slab bridge is evaluated by introducing the radar chart method. With the aid of Midas Civil, the foundation settlement characteristic of special-shaped slab bridge is analyzed, and the settlement control standard of single pier of Guang'anmen special-shaped slab bridge is determined. On this basis, the control method of composite settlement of different foundation is obtained. The finite element simulation of various conditions in the active lifting process of special-shaped slab bridge is carried out, and the reduction analysis of bearing capacity of special-shaped slab bridge is carried out in the early stage. The lifting control limit value of each pier column in the lifting process of Guang'anmen special-shaped slab bridge is obtained, and then the combined uplift control of various piers with different lifting amounts is realized. On the basis of finite element analysis, the finite element analysis is used. By comparing the results of internal force response of special-shaped plate under different lifting conditions, the optimal value of key parameters in the uplift process of special-shaped slab bridge is obtained, and the key parameters in active lifting process of special-shaped slab bridge are optimized.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U455;U443.1

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