基于RABT火灾曲线的沉管隧道管壁一维温度场解析  

Analytical Solution of 1D Temperature Field of Immersed Tube Tunnel Wall Based on RABT Fire Curve

作　　者：吴庆良 吴梦军[1,3] 邓小华 胡学兵[1,3] 曹鹏[1,3] WU Qing-liang;WU Meng-jun;DENG Xiao-hua;HU Xue-bing;CAO Peng(China Merchants Chongqing Communications Research&Design Institute Co.,Ltd.,Chongqing 400067,China;School of Engineering and Technology,Southwest University,Chongqing 400715,China;National Engineering Laboratory for Highway Tunnel Construction Technology,Chongqing 400067,China;Guangdong Communications Group Co.,Ltd.,Guangzhou Guangdong 510000,China)

机构地区：[1]招商局重庆交通科研设计院有限公司,重庆400067 [2]西南大学工程技术学院,重庆400716 [3]公路隧道建设技术国家工程实验室,重庆400067 [4]广东省交通集团有限公司,广东广州510000

出　　处：《公路交通科技》2021年第8期116-122,共7页Journal of Highway and Transportation Research and Development

基　　金：国家重点研发计划项目(2018YFC0809600,2018YFC0809603);中国博士后科学基金项目(2019M660022XB)。

摘　　要：海底隧道火灾高温会造成混凝土爆裂、力学性能劣化等严重后果,研究管壁结构厚度方向的温度场分布具有重要意义。结合沉管隧道遭受火灾时的实际工况建立了相应的数学模型,采用2次分离变量法求得RABT火灾曲线下的隧道管壁厚度方向的温度场解析解,最后以广东某沉管隧道为例对管壁结构不同位置和不同时间的温度场分布规律进行了探讨。结果表明:火灾高温对沉管管壁的影响深度在20 cm左右,由于混凝土材料的热惰性造成了温度传递的滞后,从而使得沉管管壁上各测点的时间-温度曲线和RABT曲线并不是严格一致,但在关键时间节点处仍有突变,且更靠近管壁受火面位置处的降温速度更快;在火灾恒温阶段时,管壁靠受火面位置处的温度仍然增长,并在95 min时达到最大值,甚至在火灾降温过程中,管壁靠内部位置的温度也一直在增长,并在125 min时达到最大值;降温结束后,管壁内部某些区域的温度呈现内高外低现象,即内部有较高的残余温度,后续仍有可能会对管节造成进一步的损伤。COMSOL数值计算结果与数值模拟结果相吻合,验证了解析解的正确性,能为类似工程提供参考。The high temperature of fire in subsea tunnel will cause serious results such as concrete bursting and deterioration of mechanical properties.It is of great significance to study the temperature field distribution in the thickness direction of pipe wall structures.A corresponding mathematical model is established based on the actual working conditions of the immersed tube tunnel in fire.Then,the analytical solution of the temperature field in the thickness direction of immersed tube tunnel wall under the RABT fire curve is obtained by the method of twice separate variables.Finally,taking an immersed tube tunnel in Guangdong for example,the temperature field distribution at different positions and different times of the tube wall structure is discussed.The result shows that(1)The impact depth of high fire temperature on the wall of the immersed pipe is about 20 cm.Due to the thermal inertia of the concrete material,the temperature transfer lags behind so that the time-temperature curve of each measuring point on the immersed tube wall is not strictly consistent with the RABT curve,but there are still mutation effects at key time nodes,and the cooling rate is faster at the position closer to the fire surface of the pipe wall.(2)In the constant temperature stage of fire,the temperature of the pipe wall near the fire surface still increases,and reaches the maximum value when t=95 min.Even in the process of fire cooling,the temperature near the inner part of the pipe wall increases and reaches the maximum value at t=125 min.(3)After cooling stage,the temperature in some areas inside the tube wall is higher inside and lower outside,that is,there is a higher residual temperature inside,which may cause further damage to the tube segments.(4)The COMSOL numerical calculation result is in good agreement with the analytical result,which verified the correctness of the parsing process,which could provide a reference for the similar projects.

关 键 词：隧道工程 火灾温度场 解析解 沉管 RABT曲线 

分 类 号：U458[建筑科学—桥梁与隧道工程]