【作者】 封坤；

【导师】 何川；

【作者基本信息】 西南交通大学 ， 桥梁与隧道工程， 2012， 博士

【摘要】 近年来,一大批大型跨江海水下交通通道工程相继开工建设,其中大断面水下盾构隧道不断涌现。然而,我国大断面水下盾构隧道的建设经验不多,结构设计方法尚不成熟,没有专门的设计规范,主要参考国外标准和设计方法。同时,我国幅员辽阔、不同地区地质条件差异较大,特别在水下复杂环境下既有盾构隧道建设经验并不能完全适用。鉴于此,本文针对大断面水下盾构隧道管片衬砌结构的力学行为开展研究,具有重要工程价值。论文在国家高技术发展计划(863计划)课题：“大型跨江海隧道结构力学特征及整体化设计方法研究”等国家重大研究课题资助下,采用理论分析、相似模型试验、结构原型试验与足尺试验、数值模拟分析等多种方法,对大断面水下盾构法隧道管片衬砌结构的力学性能进行了全面的、系统的研究,研究成果直接应用于我国首座水下高速铁路隧道——广深港高速铁路狮子洋隧道、南京长江隧道等重大水下盾构隧道工程之中。论文主要工作和研究成果如下：1、采用接头抗弯足尺试验和考虑接缝面界面接触效应及混凝土开裂、压溃与螺栓破坏的数值计算分析等手段,探明了大断面水下盾构隧道管片接头的抗弯性能、破坏特征以及开裂破坏的力学性能。建立了大型水下盾构隧道管片接头的接缝面抗弯力学模型,该模型能够对接缝面混凝土开裂、接头破坏等工况进行计算,弥补了以往的管片接头力学模型中不能考虑接缝大变形或破坏的不足,并提出了不同力学状态下狮子洋隧道管片接头的抗弯刚度。2、采用“盾构隧道-地层复合体模拟试验系统”与水压加载装置相结合,针对大断面水下盾构隧道承受高水压和穿越砂质土层、粘性土层、硬质岩层等多种不同性质地层的特点,开展了考虑了结构-地层-水联成作用的相似模型试验,探明了不同水、土压荷载条件、不同拼装方式、不同地层条件下管片衬砌结构的受力特征。3、采用“多功能盾构隧道结构体试验系统”对以狮子洋隧道为代表的大断面水下盾构隧道管片衬砌结构进行了原型试验,探明了正常使用阶段与开裂后管片衬砌结构的内力、形变分布与变化规律,探讨了管片拼装效应的产生机理,探明了管片衬砌结构环向内力、表面应力的分布特征。4、采用原型结构破坏试验手段,探明了管片衬砌结构最大直径变化率与最大纵缝张开量、裂缝的开展与结构刚度的变化关系,明确了不同拼装方式下管片衬砌结构的破坏特征。同时,探明了结构破坏过程中的变形特征,并从结构刚度的角度探讨了大断面水下盾构隧道破坏过程中裂缝开展、接缝张开等对结构形变的影响。5、对既有盾构隧道管片衬砌结构分析模型进行了比较,针对大断面水下盾构隧道特点提出了使用建议。通过原型试验探明了不同荷载条件、不同结构型式、不同拼装方式等条件下,结构刚度变化与管片衬砌结构的变形特性的关系,对采用匀质圆环模型开展大断面盾构隧道结构分析时的重要参数(横向刚度有效率系数、弯矩增大系数等)提出了取值建议。建立了考虑裂缝扩展的管片衬砌结构实体-接触模型,探讨了开裂破坏过程中管片衬砌结构的裂缝分布与扩展、形变发展以及应力变化特征。更多还原

【Abstract】 In recent years, a large number of cross-sea or cross-river traffic channels have been started construction in China, and most of them emerging in form of underwater shield tunnels with large cross-section. However, with regard to large cross-section shield tunnel, the structure design experience is not yet complete or consummate. There is not specific design code as reference to the design of segment structures, so the domestic designer have to consult the foreign code or design methods. Meanwhile, China has a vast territory, and the geological conditions are quite different from different regions. Especially for the complex underwater environment, the existing construction experience and design theories for shield tunnel could not be applied appropriately. In view of this, the mechanical characteristics of segmental lining structure for underwater shield tunnel with large cross-section is studied in this paper, and the results will have important practical significance.Supported by National High-Tech Research and Development Program of China (863Program):’Research on mechanical characteristics and integral design method of large underwater tunnel structures’, and many other major national research projects, the theoretical analysis, model tests, prototype tests, full-scale tests, numerical simulation and many other methods are carried out in this study. The mechanical properties of segmental structure for large underwater shield tunnel are studied comprehensively and systematically. And the research achievements are directly applied to the design and construction of several underwater shield tunnels in China, including the first high-speed railway underwater tunnel-Guangzhou Shiziyang Tunnel and Nanjing Changjiang Tunnel. The main works and research achievements include:(1) By means of full-scale tests and3D numerical analysis, which considered the joint surface interaction, properties of concrete cracking, crushing and bolt fracture, the bending behavior, failure characteristics and mechanical properties were clarified and acquired. Meanwhile, the mechanical model of segmental joint for large underwater shield tunnel was established. The model consdering the phenomenon such as cracking, crushing of concrete and yield, fracture of bolt, the models made up the defect that the previous mechanical models of segment joint could not analyze the large deformation or damage cases. The bending stiffness of segment joints of Shiziyang Tunnel was clarified under different mechanical state.(2) Using’shield tunnel-ground complex simulation facility’and’water pressure device’, Large-scale similar model tests, which considered the interaction of tunnel structure, ground and water, were carried out against the characteristics, such as high water pressure, crossing through stratas with different mechanical properties. The behavior of segmental lining structure was ascertained under different load condition, different assembling methods and different stratas.(3) Using the "Multi-function Shield Tunnel Structure Test System" device, the prototype tests were carried out agaist large-cross section underwater shield tunnel. The distribution and changes of internal forces and deformation under normal use stage, cracking damaged stage was clarified. Meanwhile, the effect of assembling method on inner force was discussed by theoretical analysis. And the distribution of circumferential internal forces and suface stress under different load conditions and different assembly methods was clarified respectively.(4) The relationships between maximum rate of diameter change, maximum longitudinal seam opening, expansion of cracks and structure stiffness was acquired by destructive prototype tests. The failure characteristics of segmental lining structure under different assembling methods were acquired respectively. Meanwhile, the deformation features during the damage process was explored, and the effect of maximum longitudinal seam opening and cracking on structure deforming was discussed in the perspective of structural stiffness.(5) Compared with the most widely-used analytical models, advises and recommendations were given according to the feature of underwater shield tunnel with large cross-section. The relationship between deformation properties and structure stiffness under different load conditions, different assembling methods and different stucrure types was acquired by prototype tests. Furthermore, suggestions on the effective bending rigidity ratios and moment increasing rates, which were key parameters of uniform rigidity ring model, were given when using the model to conduct large cross-section shield tunnel analysis. Meanwhile, solid-contact model considered crack propagation was established to discuss the distribution and stretching of cracks, the structural deformation and the stress after cracking.更多还原