盾构隧道三维数值分析方法与衬砌力学特性研究

发布时间：2018-06-09 15:50

本文选题：盾构隧道 + 装配式衬砌　；参考：《西南交通大学》2017年硕士论文

【摘要】：随着我国经济的发展和"十三五"期间城镇化进程的加快,城市公共交通的大规模建设成为必然,在建设地铁隧道时,盾构施工法由于其受施工场地和道路交通限制少,对地面生产活动影响小的优点,越来越多的成为修建城市地铁隧道的首选工法。盾构隧道装配式衬砌设计的关键问题在于计算模型本身是否能够真实反映衬砌的实际受力状态,目前用于盾构隧道装配式衬砌的横向设计计算方法有惯用法、修正惯用法、多铰圆环法、梁-弹簧模型和梁-接头模型五种;纵向设计计算方法主要有纵向梁-弹簧模型、纵向等效连续化刚度折减模型两种。上述模型都将盾构隧道装配式衬砌沿横向和纵向简化为梁结构,并且将盾构隧道的横向力学性能和纵向力学性能区分开来进行研究分析。然而,盾构隧道的结构形式非常复杂,纵向和横向的结构性能密不可分,现有的将盾构隧道横纵向简化为梁的方法很多情况下无法准确反映衬砌整体的力学性能,与实际情况出现偏差。鉴于盾构装配式衬砌结构静力学的研究现状,采用大型有限元软件ANSYS及其二次开发语言APDL对盾构隧道的接头、衬砌的数值模拟以及既有隧道内力、变形受新建隧道下穿施工的影响进行了分析研究,主要研究内容如下:(1)对盾构隧道接头进行三维有限元建模,在模型几何参数上更加接近实际设计施工情况的同时,对接头处弹性密封衬垫的力学性能和防水效应进行深入研究,并将衬垫的力学性能以本构模型的方式应用到接头三维有限元模型计算中,得到盾构管片的抗弯刚度,为壳-弹簧盾构隧道衬砌模型的接头抗弯刚度提供参数。(2)建立壳-弹簧盾构衬砌模型,以壳单元模拟混凝土管片,以弹簧单元模拟接头,对壳-弹簧模型承受不同轴力的接头进行复杂非线性抗弯刚度的自动化迭代计算,得到不同拼装方式下衬砌环的弯矩和轴力及其分布规律。(3)建立实体单元-弹簧模型,以实体单元模拟混凝土管片,以接触单元实现管片间接触作用,以不同方向的弹簧单元模拟螺栓,三者通过组合成构件的形式模拟接头的抗弯、抗拉压和抗剪非线性效应。研究了通缝、错缝拼装工况下衬砌弯矩和轴力分布的规律,并且将实体-弹簧模型,壳-弹簧模型的计算结果与惯用法和多铰圆环法进行对比分析。(4)依托国内某新建地铁盾构隧道下穿既有运营地铁隧道实际工程,对施工进行全过程计算机仿真数值模拟。采用温度应变比拟的方式,模拟了新建隧道同步注浆浆液在凝固过程中的体积缩减效应,并通过将实体-弹簧模型引入到地层中构成地层-结构计算模型,模拟既有隧道在新建盾构隧道开挖时,既有隧道的位移影响和结构内力影响。揭示了开挖过程对于既有线盾构隧道管片弯矩,轴力,螺栓受力以及管片错台,接缝张开的变化规律。
[Abstract]:With the economic development of our country and the acceleration of urbanization during the 13th Five-Year Plan period, the large-scale construction of urban public transport becomes inevitable. In the construction of subway tunnel, the shield construction method is limited by the construction site and road traffic. The advantages of little influence on ground production activities have become the preferred method for the construction of urban subway tunnels. The key problem in the design of the assembled lining of shield tunnel is whether the calculation model itself can truly reflect the actual stress state of the lining. At present, the transverse design and calculation method for the assembled lining of shield tunnel has the customary method and the modified customary method. There are five kinds of multi-hinge ring method, beam-spring model and beam-joint model, and the longitudinal design calculation methods mainly include longitudinal beam-spring model and longitudinal equivalent continuous stiffness reduction model. The above models simplify the assembled lining of shield tunnel to beam structure along the transverse and longitudinal direction, and distinguish the transverse and longitudinal mechanical properties of shield tunnel. However, the structural form of shield tunnel is very complex, and the longitudinal and transverse structural properties are inseparable. The existing methods to simplify the transverse and longitudinal of shield tunnel to beam can not accurately reflect the mechanical properties of the lining in many cases. Deviate from the actual situation. In view of the present situation of the statics research of shield assembled lining structure, the joint of shield tunnel, the numerical simulation of lining and the internal force of existing tunnel are simulated by using ANSYS and APDL, a large-scale finite element software. The deformation affected by the underpass construction of the new tunnel is analyzed and studied. The main research contents are as follows: (1) the 3D finite element modeling of shield tunnel joint is carried out, and the geometric parameters of the model are more close to the actual design and construction situation at the same time. The mechanical properties and waterproof effect of elastic seal gasket at the joint are studied in depth. The mechanical properties of the gasket are applied to the three-dimensional finite element model calculation of the joint, and the bending stiffness of shield segment is obtained by applying the mechanical properties of the gasket to the three-dimensional finite element model of the joint. To provide parameters for the joint bending stiffness of the shell spring shield tunnel lining model, the shell spring shield lining model is established. The concrete segment is simulated by the shell element and the joint is simulated by the spring element. Automatic iterative calculation of complex nonlinear bending stiffness of joints with shell spring model subjected to different axial forces is carried out, and the bending moment and axial force of lining ring and its distribution law under different assembling modes are obtained. The concrete segment is simulated by solid element, the contact action between segments is realized by contact element, the bolt is simulated by spring element in different directions, and the bending, tension and compression and shearing nonlinear effects of joints are simulated by the combination of the three elements. The distribution of bending moment and axial force of lining under the condition of jointing and assembling joint is studied, and the solid-spring model is used. The calculation results of the shell-spring model are compared with the conventional method and the multi-hinged ring method. The numerical simulation of the whole process of construction is carried out by relying on the actual project of a newly built subway shield tunnel passing through the existing operating subway tunnel in China. In this paper, the volume reduction effect of synchronous grouting in new tunnel during solidification is simulated by using temperature-strain analogy, and the solid spring model is introduced into the stratum to form a stratigraphic structure calculation model. The influence of displacement and internal force of existing tunnel on the excavation of newly built shield tunnel is simulated. The variation of the moment, axial force, bolt force, segment stagger and joint opening of the existing shield tunnel segment during excavation is revealed.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U455.43

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