高地应力挤压性地层双护盾TBM管片结构设计方法研究

发布时间：2018-01-15 00:33

本文关键词：高地应力挤压性地层双护盾TBM管片结构设计方法研究　出处：《西南交通大学》2017年硕士论文　论文类型：学位论文

【摘要】：当前双护盾TBM在国内外水工、铁路、公路、市政和地铁等隧道工程中获得了越来越广泛的应用。在双护盾TBM施工的隧道中,高地应力条件下围岩挤压现象较为普遍,并成为了工程建设中日益突出的问题。工程实例表明:围岩挤压现象是双护盾TBM管片结构破坏的重要原因之一。有鉴于此,从挤压性地层双护盾TBM隧道围岩形变及破坏特征的分析入手,在此基础之上建立挤压性地层条件下双护盾TBM管片形变压力的计算方法;结合挤压性地层条件下双护盾TBM特点建立相应的管片结构计算模型;最终提出挤压性地层双护盾TBM管片结构设计方法。本文主要研究结论如下:(1)结合挤压性地层条件下双护盾TBM掘进支护特点,探明了挤压性地层双护盾TBM隧道围岩开挖卸荷过程,围岩经历了 3次位移释放:①开挖面前方先行位移释放;②护盾区域围岩位移释放;③管片-填充层-围岩三者变形协调至稳定过程的围岩位移释放;同时探明了隧道围岩的横向破坏特征:隧道拱顶围岩易松散塌落,形成的灌浆层形变压力传导能力弱,隧道顶部地层抗力损失。(2)基于双护盾TBM隧道围岩开挖卸荷特点,建立了考虑时间因素的挤压性地层双护盾TBM管片形变压力的计算方法;提出了管片-豆砾石组合支护刚度计算公式并分析了豆砾石灌浆层的力学作用。(3)结合挤压性地层双护盾TBM支护特点,建立了豆砾石-地层综合抗力系数计算方法;通过研究近似确定了接头转动刚度与管片厚度的二次方关系,建立了基于接头尺寸效应的接头刚度计算方法;并在此基础之上形成了挤压性地层双护盾TBM管片结构计算模型。(4)通过研究管片厚度、钢筋配筋量对裂缝宽度的影响规律,建立了基于裂缝控制的挤压性地层管片截面结构设计方法;基于无衬垫式接头力学特点,提出了无衬垫式接头螺栓尺寸、材料以及锚固长度的设计方法。
[Abstract]:At present, double-shield TBM has been more and more widely used in hydraulic, railway, highway, municipal and subway tunnel projects at home and abroad. The extrusion phenomenon of surrounding rock is more common under the condition of high ground stress. It has become an increasingly prominent problem in engineering construction. Engineering examples show that the phenomenon of surrounding rock compression is one of the important reasons for the failure of TBM segment structure with double shield. Based on the analysis of the deformation and failure characteristics of the surrounding rock of the double-shield TBM tunnel in compressible strata, a method for calculating the deformation pressure of the TBM segment in the squeezed stratum is established. According to the characteristics of double shield TBM under compressible stratum, the corresponding segment structure calculation model is established. Finally, the design method of TBM segment structure in squeeze stratum is put forward. The main conclusions of this paper are as follows: 1) combined with the characteristics of double shield TBM tunneling support under the condition of squeeze stratum. The excavation and unloading process of TBM tunnel surrounding rock with double shield in compressible strata has been proved. The surrounding rock has experienced three times of displacement release: 1 ahead of excavating surface. (2) displacement release of surrounding rock in shield area; (3) displacement release of surrounding rock in which the deformation of segment, fill layer and surrounding rock is coordinated to the process of stabilization; At the same time, the transverse failure characteristics of tunnel surrounding rock are proved: the surrounding rock at the top of the tunnel is easy to collapse loosely, and the deformation pressure conduction ability of the grouting layer is weak. Based on the characteristics of surrounding rock excavation and unloading of double-shield TBM tunnel, the calculation method of deformation pressure of TBM segment of squeeze stratum with double shield is established considering time factors. In this paper, a formula for calculating the stiffness of the combined support of segment and pea gravel is put forward and the mechanical action of the grouting layer of pea gravel is analyzed. The characteristics of double shield TBM support combined with squeeze stratum are analyzed. The calculation method of comprehensive resistance coefficient of pea gravel and stratum is established. The quadratic relation between the rotational stiffness of the joint and the thickness of the segment is determined by studying and the method of calculating the stiffness of the joint based on the dimension effect of the joint is established. On the basis of this, the calculation model of double-shield TBM segment structure in squeeze stratum is formed. The influence of segment thickness and reinforcement quantity on crack width is studied. The section structure design method of squeeze stratum segment based on fracture control is established. Based on the mechanical characteristics of unpadded joint, the design method of bolt size, material and Anchorage length is presented.
【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】：U455.4

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