基于可拓理论的隧道洞口段动力响应规律研究  

Study on the Dynamic Response of Large Span Railway Tunnel Portal Based on Extension Theory

作　　者：周佳媚[1] 李瑞涵 黄柯[1] 崔凯琪 岳飞翔 Zhou Jiamei;Li Ruihan;Hunag Ke;Cui Kaiqi;Yue Feixiang(Key Laboratory of Transportation Tunnel Engineering,Ministry of Education,SouthwestJiaotong University,Chengdu 610031,P.R.China)

机构地区：[1]西南交通大学交通隧道工程教育部重点实验室,成都610031

出　　处：《地下空间与工程学报》2024年第2期625-635,共11页Chinese Journal of Underground Space and Engineering

基　　金：铁道第三勘察设计院集团有限公司设计咨询项目(院付委外[2016]城交分院006号)。

摘　　要：隧道洞口段存在偏压浅埋、围岩破碎等情况,为探究隧道洞口段在地震作用下的动力响应规律并给出安全性定量评估指标,以雅万高铁6号隧道为依托建立数值模型,分别输入雅万人工合成波、EI波、KB波以及WL波4个地震波,基于可拓理论,建立可拓物元模型,对采用数值模拟方法得出的隧道洞口段在最不利地震波作用下的弯矩、轴力、相对位移、加速度4个安全评估指标结果创建分区,以综合定量指标对雅万高铁6号隧道洞口段进行安全性评估,并提出了抗震设防长度。同时,分析了在不同地震波作用下的雅万高铁6号隧道洞口段的动力响应规律。结果表明:(1)在雅万人工波作用下,隧道各评估点动力响应程度约为其余3种天然波作用下动力响应程度的1.2倍;(2)各地震波计算所得4个评估指标沿纵向方向变化规律基本相同,轴力及弯矩峰值均出现在拱肩拱脚位置,相对位移峰值均发生在洞口处仰拱至拱顶测线,评估指标峰值发生时刻略微滞后于地震波峰值加速度对应时刻;(3)在雅万人工合成波作用下,雅万高铁六号隧道洞口段抗震设防长度为45~55 m,为隧道洞径的3.5~4倍。研究成果可为通过综合定量指标对隧道洞口段进行抗震安全性评估提供参考。There are shallow buried bias and broken surrounding rock in the tunnel portal section.In order to explore the dynamic response law of the tunnel portal section under the action of earthquake and give the quantitative evaluation index of safety,a numerical model is established based on the No.6 tunnel of Yawan high-speed railway.Four seismic waves of artificial synthetic wave,EI wave,KB wave and WL wave are input respectively.Based on the extension theory,an extension matter-element model is established.The results of four safety evaluation indexes of bending moment,axial force,relative displacement and acceleration of the tunnel portal section under the most unfavorable seismic wave are obtained by numerical simulation method,and the safety evaluation of the No.6 tunnel portal section of Yawan high-speed railway is carried out with quantitative indexes.The seismic fortification length is proposed.At the same time,the dynamic response law of No.6 tunnel portal section of Yawan high-speed railway under different seismic waves is also analyzed.The results show that;(1)Under the action of Yawan artificial wave,the dynamic response degree of each evaluation point of the tunnel is about 1.2 times that of the other three natural waves;(2)The four evaluation indexes calculated by each seismic wave have basically the same variation law along the longitudinal direction.The peak values of axial force and bending moment appear at the arch foot of the spandrel arch,and the peak values of relative displacement occur from the inverted arch to the vault line at the entrance of the cave.The peak time of the evaluation index is slightly lagging behind the corresponding time of the peak acceleration of the seismic wave.(3)Under the action of YW wave,the seismic fortification length of No.6 tunnel portal section of Yawan high-speed railway is 45~55 m,which is 3.5~4 times of the tunnel diameter.The research results can provide reference for determining the seismic fortification length of tunnel portal section by quantitative index.

关 键 词：高速铁路 隧道洞口段 数值模拟 抗震设防长度 可拓理论 

分 类 号：U25[交通运输工程—道路与铁道工程]