【作者】 易宁；

【导师】 欧阳东；

【作者基本信息】 暨南大学 ， 结构工程， 2011， 硕士

【摘要】 为了促进华南地区经济的进一步快速发展,港珠澳跨海大桥的建设正火热进行。跨海沉管隧道处于高温高湿的海洋环境中,受氯离子侵蚀严重、服役寿命要求高、可维修性差且维修成本高；沉管管节属于复杂截面大体积混凝土构件,早期裂缝控制要求极高。如何保证混凝土结构的耐久性与抗裂性、确保沉管隧道在设计基准期间不维修和少维修非常重要。因此,针对跨海沉管隧道耐久性与抗裂性开展专题研究十分必要与迫切。本文在全面论述华南地区跨海沉管隧道耐久性影响因素的基础上,针对华南地区高温高湿的海洋环境氯离子对混凝土侵蚀导致钢筋锈胀开裂引起结构耐久性损伤的原理、适用于沉管隧道的高耐久性高抗裂混凝土的制备与试验、大体积复杂截面混凝土构件水化热温度应力的参数化分析及其裂缝控制技术等问题进行了研究,建立了跨海沉管隧道重要结构耐久性与抗裂性的研究方法和理论框架体系。论文进行的工作及其创新点主要有：1)根据华南地区海洋环境,通过结构耐久性的影响因素、损伤机理以及结构耐久性寿命预测模型进行定性分析,提出混凝土耐久性主要影响因素为高温高湿高氯离子浓度的海洋环境；并综述了高温高湿环境对结构耐久性的影响研究。2)系统地总结了高耐久高抗裂混凝土的设计原则与方法,确定了采用粉煤灰和矿渣双掺,降低水化热,降低氯离子渗透系数的设计思想。并据此配制了沉管隧道用高耐久性高抗裂混凝土,通过普通力学试验、氯离子渗透试验、水化热试验优选混凝土最优配合比。3)建立复杂截面大体积混凝土早期应力有限元分析模型,系统分析预制沉管管节早期应力问题。在MIDAS平台开展水化热温度应力参数化分析,通过调整材料、施工及养护的参数寻找最优的总体方案,深入探究了各关键参数对混凝土水化热温度裂缝的影响,并确定满足裂缝控制要求的材料、施工、养护等关键技术指标。4)对早期裂缝的影响因素以及预防措施进行了系统的分析,提出了采用高耐久高抗裂混凝土,降低入模温度,室内恒温保湿保温养护等综合裂缝控制措施；结合早期应力参数化分析结果提出了危险期和危险区重点防护的裂缝控制思想和措施。论文还对大体积混凝土温度应力有限元分析软件的编程思路,前后处理中的各种分析模拟技术以及仿真分析所涉及的混凝土各种时变特性参数的模拟方法进行了探讨。更多还原

【Abstract】 In order to further promote the rapid development of regional economy, the Hong Kong-Zhuhai-Macau Bridge’s construction is carried out. Sea-crossing immersed tunnel is at high temperature and humidity in the marine environment, with the characteristics of chloride by serious, service life of high demand, poor maintenance and high maintenance costs. Immersed tunnel cube is a massive concrete structure of complex section. It is highly demanding in the early crack control. How to ensure the durability of concrete structure and crack resistance, to ensure the immersed tube tunnel in the design of the base period is not less maintenance and repair is very important. Therefore, the thematic research for the immersed tube tunnel durability and crack resistance is necessary and urgent.This article on the basis of comprehensive exposition the durability factors of immersed tube tunnel of the South China Sea,Against the principle of chloride ions of the marine environment erosion the the concrete than led to the cracking of steel corrosion and cause the damage of structure durability、applied to the preparation and test of the high durability and high cracking resistance concrete of immersed tube tunnel、studied the issues of parametric analysis and crack control technology of hydration heat temperature stress and massive concrete structures with complex cross,established the the research methodology and theoretical framework of the durability and crack resistance of the important structural of immersed tube tunnel.The work and innovation of the paper carried out mainly:1) According to the marine environment of south China, through qualitative analysis of influencing factors and damage mechanism of structure durability and the prediction model of durability lifetime are carried out,this paper proposes that the main factors affecting concrete structure durability is high-temperature and high-humidity and high chlorine ion concentration of Marine environment, and reviews the effect of high-temperature and high-humidity environment to structure durability.2) This paper summarizes design principle and method of high permanent stability and high crack resistance concrete, and determines the design ideas of double mixing fly ash and slag and decreasing hydration heat and chloride permeability coefficient.According to these, prepare high permanent stability and high crack resistance concrete using on immersed tunnel, through the common mechanical test and chloride permeability test and the hydration heat test, the optimize the optimum proportion of concrete is determined.3) In order to systematically analyze the pre-stress problems early section of immersed tunnel tube, complex cross-section of early stress in mass concrete finite element analysis model is established. This paper carries out the hydration heat temperature stress analysis In MIDAS platform and deeply investigates the effect of various parameters on the temperature cracks of concrete hydration heat by adjusting the parameters of the materials, construction and maintenance to find the optimal overall scheme, and determines the key technical indexes meeting the requirements for crack control, such as materials, construction and maintenance.4) For the influencing factors of early cracks and preventive measures, the systemic analysis is carried out. This paper proposes comprehensive crack control measures, such as using high permanent stability and high crack resistance concrete, reducing molding temperature, and so on. Combining with the early stress analysis, this paper proposes the key protective apparatus for crack control thoughts and actions.Finite element analysis software programming ideas of mass concrete temperature stress and the various simulation analysis and simulation analysis techniques involved in various time-varying parameters of concrete of the simulation method are also discussed.更多还原