复杂工况条件下错缝拼装盾构管片变形性能试验与仿真分析研究

发布时间：2019-01-25 19:14

【摘要】：现今,采用错缝拼装的通用管片形式已经在国内取得了广泛的应用,同时由于诸多的原因,某些采用此种管片形式的盾构隧道出现了结构及耐久性损伤。结构损伤会影响地铁线路的正常运营,尤其是整体变形不仅会影响到盾构隧道各项行车指标的变化,也会降低盾构管片结构的整体承载力,对盾构隧道的安全性和可靠度产生威胁。因此,通用管片的安全和使用性能受到了社会的广泛关注和运营单位的高度重视,通用管片隧道的变形机理和影响因素需要进行更深入的研究。由于地铁隧道周边城市开发的滞后性,在地铁保护区范围内进行后期施工建设不可避免,尤其是紧邻隧道的深基坑施工会对盾构结构的安全性产生较为严重的影响。深圳1号线前鲤区间在国内较早地采用了通用管片结构,并且由于周边历史堆载和降水原因,管片结构已经产生了较为严重的收敛变形和损伤。同时,深圳前海交易广场深基坑工程上跨区间盾构隧道,其基坑施工活动会对该段区间盾构隧道的运营和结构安全产生较大的影响。该现状区间隧道能否承受后续的施工荷载变化需要验证和研究。本文针对上述工程和研究需要,进行了如下方面的工作:(1)错缝拼装整环足尺试验研究结合前鲤区间历史原因造成的已有损伤,设计了包含前鲤区间200环及其邻近环的三环错缝拼装整环足尺承载力试验,确定了管片环正常使用和承载力极限受力变形状态,验证了盾构隧道在后续施工工况下的安全性和可靠性。(2)三维非线性接触有限元仿真计算同步建立了与管片试验一致的仿真模型,采用仿真重演方式进行了模型验证,通过对比分析阐述了试验管片结构的变形机理,明确了接缝位置形成塑性铰和管片环间作用对中环腰部收敛变形和破坏分布的决定性影响。对环间摩擦系数的敏感性进行了参数分析,并以此明确了管片结构的传力路径。(3)盾构隧道变形影响分析在试验仿真模型的基础上,分析了隧道顶部超载、侧向卸载、周边降水等不同工况以及封顶块不同拼装角度对盾构隧道的影响,明确了管片环顶侧加载力差值对收敛变形发展的控制性作用,以及封顶块的拼装方式对管片环变形性能的显著性影响。
[Abstract]:Nowadays, the universal segment form with staggered joints has been widely used in our country. At the same time, for many reasons, some shield tunnels with this kind of segment form have been damaged in structure and durability. Structural damage will affect the normal operation of subway lines, especially the overall deformation will not only affect the change of driving index of shield tunnel, but also reduce the overall bearing capacity of shield segment structure. It threatens the safety and reliability of shield tunnel. Therefore, the safety and performance of the universal segment have been paid more attention by the society and the operation units. The deformation mechanism and the influencing factors of the universal segment tunnel need to be further studied. Due to the lag in the development of metro tunnel surrounding cities, it is inevitable to carry out the later construction in the subway protection area, especially the construction of deep foundation pit next to the tunnel will have a serious impact on the safety of shield structure. The common segment structure was adopted in the front common carp section of Shenzhen No. 1 Line earlier in China, and the segment structure has already produced serious convergent deformation and damage due to the historical heaped load and precipitation around it. At the same time, the operation and structural safety of shield tunnel in Shenzhen Qianhai Exchange Square will be greatly affected by the foundation pit construction activity of the cross-section shield tunnel on the deep foundation pit project of Shenzhen Qianhai Exchange Square. It is necessary to verify and study whether the tunnel can withstand the subsequent construction load change. According to the above engineering and research needs, the following works have been done in this paper: (1) the full-scale experimental study of the dislocation joint assembly ring combined with the existing damage caused by the historical causes of the former common carp section, In this paper, the full-scale bearing capacity test of three-ring staggered joints including 200 rings in front carp section and its adjacent rings is designed, and the normal use of segment rings and ultimate bearing capacity deformation state are determined. The safety and reliability of shield tunnel under subsequent construction conditions are verified. (2) Three-dimensional nonlinear contact finite element simulation calculation synchronously establishes the simulation model consistent with the segment test. By comparing and analyzing the deformation mechanism of the experimental segment structure, the decisive influence of the plastic hinge formed at the joint position and the interaction between the segment ring and the segment ring on the convergent deformation and failure distribution in the waist of the ring is clarified. The sensitivity of friction coefficient between rings is analyzed, and the load transfer path of segment structure is determined. (3) on the basis of the experimental simulation model, the overload and lateral unloading of the top of the shield tunnel are analyzed. The influence of different working conditions such as peripheral precipitation and different assembling angle of roof block on shield tunnel is made clear, and the controlling effect of the difference of loading force on the development of convergent deformation is made clear. And the significant influence of the assembling method of the top block on the deformation performance of the segment ring.
【学位授予单位】：中国铁道科学研究院
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U455.43

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