火灾下盾构隧道管片构件的可靠度研究

发布时间：2018-02-28 06:41

本文关键词： 火灾盾构隧道管片构件可靠度安全性　出处：《中南大学》2014年硕士论文　论文类型：学位论文

【摘要】：摘要：随着我国城市轨道交通的发展,以及盾构修建技术的进步,越来越多交通的隧道都采用盾构法来修建。伴随而来的安全问题也越来越受到人们的关注,隧道火灾就是所关注的主要问题之一。以往的隧道火灾案例表明火灾不仅会造成重大的人员伤亡和财产损失,同时也会对隧道衬砌结构造成严重损害。盾构隧道主要由管片拼装而成,火灾会对管片造成严重损伤,导致管片结构承载力和安全性大大降低；加之盾构隧道在设计、修建、营运都存在着不确定性,如何准确定量的评价火灾下盾构隧道管片结构的承载力和安全性,就成了盾构隧道结构抗火研究的重要问题。本文在前人研究的基础上,以实际工程为背景,基于结构可靠性理论分析火灾对管片构件的影响,主要的研究工作如下： (1)在国内外火灾试验成果的基础上,选取了火灾升温曲线、混凝土材料热工参数,再通过有限元软件ABAQUS计算了管片结构的温度场,并从材料高温劣化的角度分析了管片截面的损伤规律。 (2)基于等效截面法,给出火灾下管片截面的极限承载力随受火时间的计算公式,并结合惯用法给出的盾构隧道管片内力的计算公式,建立了火灾下管片构件的功能函数。 (3)采用一次二阶矩法,对火灾下管片构件的可靠度进行了计算,分析了混凝土等级、钢筋等级、盾构隧道埋深、覆土层重度等主要因素下管片构件的可靠度随受火时间的变化规律。 (4)根据计算得到的管片构件可靠度随受火时间的变化规律,评估了管片构件的安全性,并给出了火灾后评估盾构隧道管片结构的可靠指标,以及管片结构抗火设计与防火建议。
[Abstract]:Abstract: with the development of urban rail transit and the progress of shield construction technology, more and more tunnels are built by shield tunneling. Tunnel fire is one of the main problems concerned. Past tunnel fire cases show that fire not only causes heavy casualties and property losses. At the same time, it will also cause serious damage to the lining structure of the tunnel. The shield tunnel is mainly composed of segments, and the fire will cause serious damage to the segments, which will lead to a great decrease in the bearing capacity and safety of the segment structure. In addition, the shield tunnel is being designed and built. There is uncertainty in operation. How to evaluate accurately and quantitatively the bearing capacity and safety of shield tunnel segment structure under fire is an important problem in the research of shield tunnel structure fire resistance. Based on the theory of structural reliability, the influence of fire on segment members is analyzed in the background of actual engineering. The main research work is as follows:. 1) on the basis of the fire test results at home and abroad, the fire heating curve and the thermal parameters of concrete are selected, and the temperature field of the segment structure is calculated by the finite element software ABAQUS. The damage law of the section is analyzed from the point of view of material degradation at high temperature. 2) based on the equivalent section method, the calculation formula of the ultimate bearing capacity of the section under fire with the time of fire is given, and the function function of the segment member under fire is established by combining the formula of the internal force of the shield tunnel segment given by the customary method. The reliability of segment members under fire is calculated by using the first-order second-order moment method, and the concrete grade, reinforcement grade and the buried depth of shield tunnel are analyzed. The variation rule of reliability of segment components with fire time under the main factors such as overburden depth and so on. 4) according to the rule that the reliability of segment member changes with the time of fire, the safety of segment member is evaluated, and the reliability index for evaluating the segment structure of shield tunnel after fire is given, as well as the fire resistance design and fire prevention suggestion of segment structure.
【学位授予单位】：中南大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U455.43

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