超大直径双层盾构隧道火灾高温下衬砌结构力学特性分析  

Analysis of Mechanical Characteristics of Lining Structure of Super Large Diameter Double-layer Shield Tunnel Exposed to High Temperature

作　　者：李策 LI Ce(China Railway SIYUAN Survey and Design Group CO.,LTD,Wuhan 430063)

机构地区：[1]中铁第四勘察设计院集团有限公司隧道院,武汉430063

出　　处：《铁道勘测与设计》2022年第1期62-68,共7页Railway Survey and Design

摘　　要：为研究超大直径双层盾构隧道内部发生火灾时,火灾高温对隧道衬砌结构力学特性的影响规律,本文以某双层盾构隧道为例,采用有限元计算软件,建立了双层盾构隧道热力耦合模型,得出了超大直径双层盾构隧道在火灾高温下衬砌结构的变形及受力规律,研究结果表明:发生火灾时,火灾高温逐步侵入隧道结构内部,距离受火面越近温度越高;火灾初始阶段,热对流区衬砌温度上升明显缓于热传导区,随着火灾高温持续,两区域衬砌温度逐渐趋于一致;下层空间发生火灾会导致上层行车道板下部产生较大的膨胀变形,内部钢筋屈服;隧道内施做防火措施可极大阻隔火灾高温热量的传递,降低管片衬砌内部温度,减小隧道结构的热膨胀变形,减小隧道结构应力,提升隧道的火灾安全性,在双层盾构隧道内施做防火措施十分有必要。本文所得结论可为类似工程提供借鉴参考。In order to study the influence of the fire temperature on the mechanical properties of the tunnel lining structure when a fire occurs inside a super large-diameter double-layer shield tunnel,this paper takes a double-layer shield tunnel as an example and uses finite element calculation software to establish a thermo-mechanical coupling model of double-layer shield tunnel which obtained the deformation and force law of the lining structure of the super-large-diameter double-layer shield tunnel exposed to the high temperature.The research results show that when a fire occurs,the high temperature of the fire gradually penetrates into the tunnel structure.The closer the distance to the fire surface is,the higher the temperature of the tunnel structure.In the initial stage of the fire,the temperature rise of the lining in the heat convection zone is obviously slower than that in the heat conduction zone.As the fire continues,the lining temperature of the two areas gradually tends to be the same;A fire in the lower space will cause large expansion and deformation of the lower part of the upper carriageway board,and the internal steel bars will yield;Fire prevention measures in the tunnel can greatly block the transfer of high-temperature heat in the fire,reduce the internal temperature of the lining structure,reduce the thermal expansion and deformation of the tunnel structure,reduce the stress of the tunnel structure,and improve the fire safety of the tunnel.It is necessary to implement fire prevention measures in the double-layer shield tunnel.The conclusions obtained in this article can provide references for similar projects.

关 键 词：双层盾构隧道 热力耦合 火灾温度荷载 衬砌结构 力学特性 

分 类 号：U45[建筑科学—桥梁与隧道工程]