高温下盾构隧道接缝结构受力特性分析及可靠度研究

发布时间：2018-01-28 11:41

本文关键词： 地铁盾构管片接头火灾高温可靠度分析　出处：《中南大学》2014年硕士论文　论文类型：学位论文

【摘要】：摘要：随着国内地铁的快速发展,盾构隧道建设项目也逐渐增多。伴随而来的安全问题,尤其是火灾下盾构隧道的结构安全,成为了现有关注的热点之一。盾构隧道是由管片通过接头拼装而成的,一旦发生火灾,不仅管片构件会发生损伤,作为薄弱环节的接缝结构在高温下的受力特性,其也将对隧道结构安全造成极大的损害；同时,接缝结构是隧道防水的关键,其高温下的灾变行为,如接缝变形过大导致漏水等,将极大的影响盾构隧道的使用功能。可见,如何确定高温下盾构隧道接缝结构的受力特性,并以此为依据评估其安全性及可靠性,是未来盾构隧道火灾评估的关键。因此本文针对高温下盾构隧道接缝结构受力特性进行以下研究： 1.建立接头结构三维数值模型,确定火灾下接缝结构的温度分布规律,重点研究高温下手孔局部及连接螺栓的升温历程；揭示不同轴力、偏心距荷载组合下的接缝结构张开量变化规律；探究高温作用过程中螺栓与混凝土结构的应力应变变化规律,并分析接缝结构受压区高度变化规律。 2.基于接头结构常温受力模型,考虑接缝结构衬垫的影响,结合数值模拟结果,分析了接缝在装配-正常运营-火灾高温全过程下的力学行为和变形机理；建立了高温下接头结构受力模型,制定高温下接缝结构接头刚度理论计算方法,并根据数值模拟给出的温度场结果进行计算,进而与数值模拟结果进行对比分析,验证理论算法的可行性。 3.基于接缝结构在火灾高温下的力学模型,分析盾构隧道接缝结构高温失效模式,给出火灾高温下接头结构的失效功能函数,并以此为依据结合验算点法计算衬垫厚度、螺栓位置、衬砌厚度等不同参数对接缝结构可靠度的影响规律；结合可靠度分析及数值模拟结果,给出了相应的地铁盾构隧道接缝防火建议。
[Abstract]:Absrtact: with the rapid development of subway in China, the construction project of shield tunnel is increasing gradually. The safety problems come with it, especially the structural safety of shield tunnel under fire. Shield tunneling is made up of segments assembled by joints. Once fire occurs, not only segment members will be damaged. As a weak link, the mechanical characteristics of jointed structure under high temperature will also cause great damage to the safety of tunnel structure. At the same time, joint structure is the key of tunnel waterproofing, its catastrophic behavior under high temperature, such as joint deformation too large lead to water leakage, will greatly affect the use of shield tunnel function. How to determine the mechanical characteristics of shield tunnel joint structure under high temperature and evaluate its safety and reliability. It is the key to fire assessment of shield tunnel in the future. Therefore, the stress characteristics of joint structure of shield tunnel under high temperature are studied as follows: 1. To establish a three-dimensional numerical model of joint structure, determine the temperature distribution of joint structure under fire, and focus on the temperature rise process of high temperature underhole and joint bolt; The variation law of opening quantity of joint structure under different axial force and eccentricity load combination is revealed. The variation of stress and strain of bolt and concrete structure under high temperature is studied, and the variation law of height in compression zone of jointed structure is analyzed. 2. Based on the stress model of joint structure at room temperature, considering the influence of the gasket of joint structure, combined with the numerical simulation results, the mechanical behavior and deformation mechanism of joint in the whole process of assembly, normal operation and fire high temperature are analyzed. The stress model of joint structure under high temperature is established, and the theoretical calculation method of joint stiffness of joint structure at high temperature is established, and the results of temperature field are calculated according to the numerical simulation. And then compared with the numerical simulation results to verify the feasibility of the theoretical algorithm. 3. Based on the mechanical model of joint structure under high temperature, the failure mode of shield tunnel joint structure at high temperature is analyzed, and the failure function function of joint structure under fire high temperature is given. On the basis of this, the reliability of butt joint structure of different parameters, such as cushion thickness, bolt position, lining thickness and so on, is calculated based on checking point method. Combined with reliability analysis and numerical simulation results, the corresponding fire prevention suggestions of shield tunnel joint are given.
【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】：U451;U455.43

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