【作者】 郑余朝；

【导师】 仇文革；

【作者基本信息】 西南交通大学 ， 桥梁与隧道工程， 2007， 博士

【摘要】 随着经济的不断发展，我国对基础设施，尤其是交通设施建设的需求在不断增加，目前，铁路、公路正进行着大规模的建设。路网的完善和扩能，提速及高速路网的发展，西部大开发战略的实施和大城市的发展，出现了大量地下工程及隧道的近接施工问题。而隧道经典理论主要基于半无限体或无限体中单一洞室的力学行为，大量的近接施工研究多基于经验和个案研究，系统性研究较少。从现行国内设计规范来看，主要基于弹性解的无影响范围和经验值，或仅限于个别类型的相关规定，缺乏必要而充分的理论分析。因此有必要对理论进行新的发展，为规范和指南的制定提供依据。本文以上海轨道交通9号线R413项目三孔并行盾构隧道下穿铁路和自身近接的工程问题为依托，结合建设部三孔并行软土地铁盾构隧道的控制技术研究课题，综合运用调查研究、数值分析、模型试验、现场测试和经验类比方法，在归纳总结和批判吸收的基础上，对盾构隧道下穿铁路近接施工和三孔并行盾构隧道的近接施工的特殊性和普遍性问题进行研究，得到了以下主要成果和结论：1、本文在文献[1]相关近接理论的基础上，定义了几何近接度和近接影响度的概念，提出了近接影响度和近接影响分区的表达式，并将近接影响分区限定在常规措施条件下，完善了文献[1]提出的相关理论。2、研究了基于地表沉降判别准则的不同影响度或分区的相关阈值；提出了钢筋混凝土结构的强度判别准则表达式和相关分区阈值；基于变化影响程度的概念，提出强度判别准则比和相关阈值；提出以动静荷载比作为分析列车动载对下伏隧道影响的强度判别准则。3、根据近接影响度和影响分区理论，运用统计力学方法，分别基于地表位移判别准则、结构强度判别准则，以及动静荷载比判别准则对近接影响度表达式中的几何近接度影响修正系数α_0ij，埋深影响的修正系数α_4ij和综合系数K_ij进行了研究，并得到了基于埋深比（H／D）—几何近接度A，或应力比（R_b／σ₀）—几何近接度A的近接影响分区。4、利用平面、三维数值模拟，离心模型试验和现场测试研究了三孔并行盾构隧道近接施工的应力场、位移场和结构内力的演变规律，指出了近接施工的控制关键及其力学原理，阐述了盾构施工参数分级的思路，并研究了对策措施分级以分别与常规近接影响度相对应。5、采用死活单元法、刚度和荷载迁移法模拟了盾构的推进，利用软弱实体和逐步增大弹模的方法模拟了惰性浆液的注入和硬化，利用温度的升降产生的膨胀和收缩效应模拟了注浆压力和压力的消散；利用水囊定量注放水的方式在离心模型实验中模拟了盾构施工的地层损失；建立了三维动力有限元模型，模拟了上下行列车同时对向行驶的轮载的移动，实现了列车动载作用下的土—结构动力分析；大量采用影响线方法对近接施工的力学行为进行了分析；建立了基于隧道拱顶动土压力的平面简化计算模式。6、得到了三孔并行盾构隧道个案和普遍性研究的一些结论。本文主要针对三孔并行盾构隧道的同步近接情况，地质条件也仅限于类似R413工程的地层，在影响因素上也只对几何近接度和埋深的影响进行了研究。由于近接施工类型和影响因素繁多，需要加大力度划分类型和影响因素进行研究。尤其是应用较多的几个近接类型，应该重点突破，力求尽快完善和建立影响分区的指标体系，为规范和指南的编制提供依据，以指导设计、施工和管理。更多还原

【Abstract】 With the boost of economy, the demand of infrastructure is increasing, especially in means of transportation. Lots of cases of adjacent construction in tunnel and underground project had appeared in the perfection of traffic net. Tradition theory is based on the mechanical behaviors of single cavern in semi-infinite or infinite medium, while most of the researches on adjacent construction are based on experience and case study with a little systematic study. It seems from actual design norms in China that such researches are mainly based on non-influential zone of elastic solution and empirical value, or separate model, which lack of necessary and sufficiency theoretical analysis. For framing norms and guides, it’s necessary to do some research on the theory.This dissertation carried out a study on the particularity and universality of the adjacent construction which depends on the project of R413 in the ninth line of shanghai track traffic, by using the methods of investigation and study, numerical analysis, model test, in-situ test and analog.The following achievement and outcome was gained:1. This dissertation develops the theory of literature [1] by defining geometric adjacent degree and adjacent influence degree, putting forward the expressions of adjacent influence degree and adjacent influence subzone and limiting the adjacent influence subzone to normal procedure measures.2. This dissertation researches coherent threshold of different influence degrees and subzones based on the criterion of Land subsidence, and puts forward the criterion expression of reinforced concrete strength and coherent threshold. Ratio threshold of strength and coherent threshold based on the concept of influence grade are given. And so is the using of the ratio of dynamic and static load as the strength criterion of analyzing dynamic load of train acts on the tunnel.3. In this dissertation, according to the definitions of adjacent influence degree and influence subzone, the coefficient of the geometric adjacent degreeα_0ij, the one influence by depthα_4ij, and the synthesis coefficient K_ij are studied by using statistical mechanics, with the base of the land displacement criterion, strength criterion and the criterion of ratio of dynamic and static load. Therefore the influence subzones based on ration of depth （H/D） with geometric adjacent degree A, or the stress ratio （R_b/σ₀） are put forward.4. By the use of 2D and 3D numerical simulation, centrifugal model experiment and in-situ test, the stress field, displacement field and the regularity of inner force are studied. And the control key and mechanics principles are indicated. Therefore, the classifying process of parameter in shield construction and classifying of countermeasures that correspond with the conventional adjacent degree are studied.5. In this dissertation, the driving of the shield is simulated by the method of dead and live element and the stiffness and load migration. The filling and hardening of inert fluid are simulated by the use of weak solid mass and gradually increasing the modulus of elasticity. And the pressure of injecting and the dissipation of the pressure are simulated by the expansion and contraction effect brought by temperature. The loss of soil in the ground in shield driving is simulated by the method of injecting and releasing certain amount of water contained in pockets. A three-dimensional finite element model is established in this dissertation to simulate the movement of the wheel load when the trains are vis-a-vis with each other, and the dynamic analysis with the interaction of solid and stricter is realized. This dissertation also uses the influence line method greatly to analyze the mechanical behavior of adjacent construction, and establishes a simplified model in plane based on the dynamic earth pressure of vault.6. Some conclusions about the shield tunnel cases and the universality study of three-pore tunnel were gained.This dissertation mainly deal with the research on synchronous adjacent situation of three parallel tunnel that constructed by shield, which geological conditions are similar with the project of R413. And in the aspect of influencing factors, only the influence of geometric adjacent degree and depth are researched. Much more work should be done type by type and factor by factor because of the great numbers of adjacent construction types and influence factors. For framing norms and guides to direct the design, construction and management, the index system of influencing subzone should be established and perfected as soon as possible by putting the emphasis on a few adjacent tunnel types that are in common use.更多还原