盾构隧道管片衬砌结构稳定性问题研究

发布时间：2018-03-24 01:00

  本文选题：盾构隧道　切入点：管片衬砌　出处：《西南交通大学》2014年博士论文

【摘要】：伴随着大批城市地铁盾构隧道和水下大型铁路、公路盾构隧道的建成,盾构隧道的长期安全稳定问题随之而来。目前盾构隧道衬砌结构设计理论主要从局部的管片混凝土的强度、混凝土的开裂以及接缝面的强度、接头的张开等方面进行检算,而对盾构隧道的整体失稳破坏问题缺乏考虑。实际工程中,软弱地层条件,管片结构材料性能退化以及人类活动的影响,比如近接建筑物的施工、抽取地下水等因素都会对整个盾构隧道的稳定性产生不良影响,而目前缺乏相关的理论判据,并且目前的相关研究甚少。论文结合国家重点基础研究发展计划(973计划)课题“复杂环境作用下地下结构的长期安全性及其预测方法”和国家自然科学基金青年基金“大断面盾构隧道管片接头力学行为研究”,主要采用理论分析、相似模型试验和数值分析等研究手段,对盾构隧道管片衬砌结构的稳定性问题进行研究,旨在揭示盾构隧道管片衬砌结构的失稳性态,探明盾构隧道管片衬砌结构的失稳破坏判定标准,主要工作和研究成果如下：1、针对目前我国存在的典型盾构隧道,即一般城市地铁盾构隧道和水下公路或铁路盾构隧道,采用数值分析的手段,对外直径分别为6m级、10m级、15m级的盾构隧道管片接头的抗弯性能进行了研究,给出了其盾构隧道管片接头的抗弯刚度设计建议取值范围。2、以外径10.8m的狮子洋水下铁路盾构隧道为研究对象,采用数值分析的手段,探讨了接头抗弯刚度对管片衬砌结构变形和内力的影响规律,建立了基于接头抗弯刚度-弯矩-轴力非线性关系的壳-弹簧管片衬砌力学计算模型,探明了与管片结构受力一致的管片接头抗弯刚度,对管片接头的工作性态有了较准确的把握,有利于优化设计3、采用非线性有限元稳定性分析方法,分析不同地层条件、不同接头抗弯刚度、不同拼装方式下的管片衬砌结构失稳力学特征,探讨了不同因素对盾构隧道结构稳定性的影响程度和影响规律。4、采用“盾构隧道-土层复合体模拟试验系统”,针对标准贯入度≤5的软弱粘土地层条件,开展了盾构隧道管片衬砌结构稳定性相似模型试验,揭示了接头抗弯刚度、拼装方式、管片刚度、地层空洞等不同因素对管片结构稳定性的影响规律,探明了盾构隧道管片结构的失稳性态。通过比较模型试验和数值分析的结果,提出了盾构隧道管片结构失稳破坏判断的建议。5、采用非线性有限元稳定性分析方法,研究特殊条件下的管片衬砌结构稳定性,包括局部地层抗力削弱情况、复合地层条件、地下水位变化以及长期地下环境作用引起的结构性能退化等,揭示了不同条件下管片结构的失稳机理和失稳性态。
[Abstract]:With a large number of urban subway shield tunnels and large underwater railways, the construction of highway shield tunnels, At present, the design theory of shield tunnel lining is mainly based on the strength of local segment concrete, the crack of concrete, the strength of joint surface, the opening of joint, and so on. However, the overall instability of shield tunnel is not considered. In actual engineering, the condition of weak stratum, the degradation of material performance of segment structure and the influence of human activity, such as the construction of adjacent buildings, The extraction of groundwater and other factors will have a negative impact on the stability of the whole shield tunnel, but there is no relevant theoretical criterion at present. And there are few related researches at present. The thesis combines with the national key basic research and development plan "the long-term safety of underground structure under complex environment and its prediction method" and the youth of the National Natural Science Foundation of China ("the long-term safety of underground structure under the action of complex environment and its prediction method"). The research on the mechanical behavior of segment joint of large-section shield tunnel is mainly based on theoretical analysis. Similar model test and numerical analysis are used to study the stability of shield tunnel segment lining structure in order to reveal the unstable state of shield tunnel segment lining structure. The main work and research results are as follows: 1. Aiming at the typical shield tunnel existing in our country at present, that is, the general urban subway shield tunnel and the underwater highway or railway shield tunnel, By means of numerical analysis, the bending behavior of shield tunnel segment joints with external diameters of 6m or 10m or 15m respectively is studied. The flexural stiffness of the segment joint of shield tunnel is given in this paper. The suggested value range of bending stiffness of the segment joint of shield tunnel is 0.2. Taking the shield tunnel of Lion-yang underwater railway with the outer diameter of 10.8m as the research object, the method of numerical analysis is adopted. The influence of joint bending stiffness on the deformation and internal force of segment lining structure is discussed, and a mechanical calculation model of shell spring segment lining is established based on the nonlinear relationship between bending stiffness, bending moment and axial force of joint. The bending stiffness of the segment joint which is consistent with the stress on the segment structure is proved, and the working behavior of the segment joint is accurately grasped, which is beneficial to the optimum design 3. The nonlinear finite element stability analysis method is used to analyze the different stratum conditions. The unstable mechanical characteristics of segment lining structure under different joint bending stiffness and different assembling methods, This paper discusses the influence of different factors on the structural stability of shield tunneling. 4. "Shield tunnel-soil complex simulation test system" is adopted to deal with the soft clay formation conditions with standard penetration 鈮，

本文编号：1655970