摘要
城市隧道合建结构发生火灾时,会对其合建相邻结构的变形及应力分布造成一定影响,进而威胁整体结构的抗火安全性能。以义乌商城大道隧道工程为依托,采用有限元软件ANSYS建立合建结构热-力耦合瞬态分析模型,考虑火灾高温对材料性能的非线性影响,依据隧道结构抗火安全性标准对不同火灾模式下合建结构的整体抗火安全性能进行分析。研究结果表明,火灾高温作用使得地下合建结构发生显著的应力重分布,但由于混凝土材料的热惰性,将不会对与受火结构合建的相邻结构内部温度场造成影响;当隧道火灾规模为30 MW且持续120 min时,受火结构表面最高温度可达673.5℃,且距离受火面25 mm处的温度为483.3℃,均不满足结构抗火安全性的温度标准,需采取一定的防火措施;且受火结构对与其水平合建的相邻结构应力及安全性有较大影响,其应力变化幅度最大超过50%,而对竖向合建结构影响较小,但均能保证整体结构体系的承载能力;建议施作导热系数小于0.15 W/(m·℃),厚度大于12 mm的防火涂料以降低火灾所引起的结构高温应力及损伤,进一步提高合建结构整体抗火安全性能。
When a fire occurs in an urban tunnel integrated structure,it will affect the deformation and stress distribution of adjacent structures,and then threaten the fire resistance performance of the integrated structure.Taking the tunnel project of Shangcheng Avenue in Yiwu as the background,the transient thermal-mechanical coupled finite analysis model of the integrated structure was established by using finite element software ANSYS.Considering the non-linear effect of high temperature on material properties,the holistic fire resistance performance of the integrated structure under different fire scenarios was studied based on the fire safety standards of tunnel structures.The results show that the stress redistribution occurs in the underground integrated structure under fire,and due to the thermal inertia of concrete,it does not affect the internal temperature field of the adjacent structures.When the tunnel fire with a scale of 30 MW lasts 120 minutes,the maximum temperature on the surface of the structure can reach 673.5℃,and the temperature at 25 mm away from the heated surface is 483.3℃,which does not meet the temperature standard of structural fire safety,then some fire prevention measures are required.The fire-affected structure has a great influence on the stress and safety of its adjacent horizontal integrated structures,and the maximum stress variation range is more than 50%,while has little influence on other integrated structures,but it can ensure the bearing capacity of the holistic structure system.And it is suggested that the fire-retardant coating with thermal conductivity less than 0.15 W/(m·K)and thickness greater than 12 mm should be applied to reduce the high temperature stress and fire-induced damage,which can further improve the holistic fire resistance performance of the integrated structure.
作者
田源
王明年
郭晓晗
胡萧越
闫自海
TIAN Yuan;WANG Mingnian;GUO Xiaohan;HU Xiaoyue;YAN Zihai(School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China;Key Laboratory of Transportation Tunnel Engineering of Ministry of Education,Southwest Jiaotong University,Chengdu 610031,China;POWERCHINA Huadong Engineering Corporation Limited,Hangzhou 311122,China)
出处
《铁道科学与工程学报》
CAS
CSCD
北大核心
2020年第8期2065-2074,共10页
Journal of Railway Science and Engineering
基金
中国铁路总公司科技研究开发计划课题(K2018G012)
四川省科技计划项目(2018JY0566)。
关键词
城市隧道
合建结构
抗火性能
安全系数
防火涂料
urban tunnel
integrated structure
fire resistance
safety factor
fire-retardant coating
作者简介
通信作者:王明年(1965-),男,安徽舒城人,教授,博士,从事隧道与地下工程设计理论及通风防灾研究;E-mail:wangmingnian@swjtu.edu.cn。
