火灾下盾构隧道纵缝完全热力耦合模型及特性分析  

Fully coupled thermo-mechanical model and performance analysis of shield tunnel longitudinal joint in fire

作　　者：沈奕 汪文忠[1] 闫治国 朱合华[1,2] Shen Yi;Wang Wenzhong;Yan Zhiguo;Zhu Hehua(Department of Geotechnical Engineering,College of Civil Engineering,Tongji University,Shanghai 200092,China;State Key Laboratory for Disaster Reduction in Civil Engineering,Tongji University,Shanghai 200092,China)

机构地区：[1]同济大学土木工程学院,上海200092 [2]同济大学土木工程防灾国家重点实验室,上海200092

出　　处：《土木工程学报》2023年第3期107-115,共9页China Civil Engineering Journal

基　　金：上海市青年科技英才扬帆计划(20YF1451400)。

摘　　要：为研究火灾下盾构隧道纵缝的受力性能,通过理论分析和数值方法建立火灾高温热流侵入情况下纵缝的完全热力耦合模型。利用火灾试验验证模型的有效性,然后基于此模型从温度、变形和内力角度对火灾下不同变形状态和初始荷载等级下接缝的力学特性进行数值分析。结果表明:当接缝初始内侧张开时,接缝结构变形发展较快,随着热流也不断侵入接缝,使得接缝附近混凝土及螺栓温度显著升高。初始负荷度越大,接缝结构变形发展越充分,接缝跨中位移和内侧张开增量变化量越大。由于在升温阶段接缝内侧张开持续发展,升温阶段的热流侵入深部也随初始变形的增加而提前,接缝的耐火时间呈现非线性加速下降。在盾构隧道的防火设计中应加强对纵缝的保护,防止纵缝在火灾下受到高温的持续侵袭。In order to study the mechanical performance of longitudinal joints of shield tunnel in fire, a fully coupled thermo-mechanical model of longitudinal joints under the condition of elevated-temperature heat flow intrusion was established by theoretical analysis and the numerical method, and then the model was validated by fire test results.Based on this model, the mechanical behaviors of the joints were analyzed numerically under different deformation states and different initial loading levels from the perspectives of temperatures, deformations and internal forces.The research results show that the temperature field and deformation of longitudinal joints are obviously affected by the boundary conditions of bearings.When the initial inner side of the joint opens, the deformation of the joint structure develops rapidly, and the temperatures of the concrete and bolts nearby the joint also increase significantly with the heat flow constantly invading the gap of joint.The larger the initial load degree is, the more sufficient the deformation of the joint structure develops, and the greater the increment of the mid-span displacement and the inner side opening of the joint shall be.Due to the continuous development of joint opening in the heating stage, the heat flow invasion into the deep position in the heating stage shall be earlier with the increase of the initial deformation.During this procedure, the fire resistance of the joint exhibits a nonlinear accelerated decline.In the fire prevention design of shield tunnel, the protection of longitudinal joints should be strengthened to prevent from being continuously damaged by elevated temperatures in fire.

关 键 词：火灾 盾构隧道 纵缝 热力耦合模型 特性分析 

分 类 号：TU921[建筑科学—建筑设计及理论]