盾构隧道管片接头高温力学行为与结构剩余承载力研究

发布时间：2018-07-24 11:18

【摘要】：隧道防火研究不再局限于烟雾控制和人员疏散方面的研究,大量案例表明火灾会对衬砌结构造成严重损坏。管片接头作为盾构隧道衬砌结构的薄弱环节,如何正确评价管片接头高温性能是研究盾构隧道衬砌结构的抗火性能的基础。本文采用数值模拟及理论分析等手段,研究了盾构隧道管片接头高温力学行为、管片构件及衬砌结构承载性能,取得了以下研究成果： (1)建立管片接头二维热力耦合分析模型,分析盾构隧道管片接头高温力学行为,获得了接头温度场、内力重分布及接缝变形的变化规律。通过探讨管片接头高温下抗弯性能,得到了不同受火时间下的管片接头抗弯刚度劣化规律。 (2)分析管片材料高温试验结果获得了高强混凝土、钢筋的高温力学性能劣损规律。以衬砌材料高温力学参数为基础,结合管片构件高温极限承载力试验和理论推导,提出了符合隧道火灾特点的极限承载力简易积分法。 (3)基于荷载结构法及梁-弹簧模型,考虑火灾高温作用导致的衬砌结构强度及刚度非均匀劣化,构建考虑火灾作用的梁-弹簧盾构隧道结构内力计算模型。归纳总结火灾场景的确定方法并提出了管片刚度及接头刚度计算方法。 (4)提出了盾构隧道火灾后剩余承载力计算程序模型,该模型以梁-弹簧模型法为荷载效应计算方法,利用极限承载力简易积分法计算结构抗力并采用极限承载力包络图判定结构承载安全性。
[Abstract]:The study of tunnel fire prevention is no longer confined to the study of smoke control and evacuation. A large number of cases show that the fire will cause serious damage to the lining structure. Segment joint is the weak link of shield tunnel lining structure. How to correctly evaluate the high temperature performance of segment joint is the basis of studying the fire resistance of shield tunnel lining structure. By means of numerical simulation and theoretical analysis, the high temperature mechanical behavior of segment joint of shield tunnel, the bearing capacity of segment members and lining structure are studied in this paper. The following research results are obtained: (1) the two-dimensional thermo-mechanical coupling analysis model of segment joint is established, and the mechanical behavior of shield tunnel segment joint at high temperature is analyzed, and the variation of temperature field, internal force redistribution and joint deformation are obtained. By discussing the bending behavior of segment joint at high temperature, the degradation law of bending stiffness of segment joint under different fire time is obtained. (2) High strength concrete is obtained by analyzing the high temperature test result of segment material. The failure rule of high temperature mechanical properties of steel bar. Based on the mechanical parameters of lining materials at high temperature, combined with the test and theoretical derivation of high temperature ultimate bearing capacity of segment members, A simple integration method for ultimate bearing capacity is proposed, which accords with the characteristics of tunnel fire. (3) based on the load-structure method and the beam-spring model, the strength and stiffness of lining structure due to fire high temperature are considered. The internal force calculation model of beam-spring shield tunnel structure considering fire action is constructed. The methods of determining the fire scene are summarized and the calculation methods of segment stiffness and joint stiffness are put forward. (4) the program model for calculating residual bearing capacity of shield tunnel after fire is proposed. In this model, the beam-spring model method is used to calculate the load effect, the simple integral method of ultimate bearing capacity is used to calculate the resistance of the structure and the envelope diagram of the ultimate bearing capacity is used to determine the bearing safety of the 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】：U451.4;U458

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