斜交型立体交叉隧道的地震动力响应研究  

Study on Seismic Dynamic Response of Oblique Overlapped Tunnels

作　　者：雷浩 吴红刚 孟庆一 何长江 李德柱 LEI Hao;WU Honggang;MENG Qingyi;HE Changjiang;LI Dezhu(School of Civil Engineering,Lanzhou Jiaotong University,Lanzhou 730070,Gansu,China;Northwest Research Institute Co.,Ltd.of CREC,Lanzhou 730070,Gansu,China;Dalian Branch,China Railway No.9 Group Co.,Ltd.,Dalian 116031,Liaoning,China)

机构地区：[1]兰州交通大学土木工程学院,甘肃兰州730070 [2]中铁西北科学研究院有限公司,甘肃兰州730070 [3]中铁九局集团有限公司大连分公司,辽宁大连116031

出　　处：《隧道建设（中英文）》2021年第1期88-99,共12页Tunnel Construction

基　　金：国家重点研发计划资助项目(2018YFC1504901,2018YFC1504903);中铁九局集团有限公司大连分公司科技开发项目(KJ-2019-01)。

摘　　要：为探究立体交叉隧道在地震荷载作用下的动力响应并对立体交叉隧道的抗震设计提供理论参考,通过大型振动台试验,分别研究加载X单向及XZ双向El-Centro波时,斜交型立体交叉隧道的上跨和下穿隧道及交叉区段坡体内部加速度峰值的分布规律。试验结果表明:1)上跨及下穿隧道拱顶加速度峰值在交叉段中心断面处最大,影响区段两侧断面较小,呈现出“抛物线”分布,表明拱顶易成为立体交叉隧道抗震的薄弱环节;2)由于下穿隧道及空间效应的存在,导致上跨隧道交叉断面仰拱处的地震响应较拱顶而言明显减弱,同时下穿隧道仰拱交叉段中心断面处动力响应最小,即仰拱破坏模式表现为影响区段两侧断面—交叉段中心断面的传递演化形式;3)坡体内部交叉中心段的加速度响应存在叠加效应,导致该点的地震响应最为强烈,且其余测点的加速度放大系数随着埋深的增大而逐渐减小;4)在加载XZ双向地震波时,其同一测点的动力响应相较于只加载X单向时显著增长,且在高地震烈度(0.4g~0.6g)时这种增长现象的变化幅度较大;此外,地震波加载方向的改变对立体交叉隧道仰拱处的地震响应产生不同影响。To explore the dynamic response of overlapped tunnels under the action of seismic loads and provide a theoretical reference for the seismic design of overlapped tunnels,the distribution laws for peak acceleration values of upper and lower tunnels and cross-section of oblique overlapped tunnels are studied using a large-scale vibration test platform under X unidirectional and XZ bidirectional El-Centro waves,respectively.The results show that:(1)The peak acceleration at the central cross-section of the overlapped tunnels is the highest,whereas those at the cross-sections of the ends of the tunnels are significantly less;as such,the peak acceleration curve has a parabolic shape,indicating that the crown of the overlapped tunnel would be the weak point during earthquake resistance.(2)The seismic response of the invert at the cross-section of the upper tunnel is significantly weaker than that of the crown because of the undercrossing tunnel and spatial effect.Moreover,the dynamic response at the central cross-section of the invert of the undercrossing tunnel is the lowest,indicating that the failure mode of the invert shows a transmission evolution from both sides of the affected cross-section to the central cross-section.(3)Superposition effect is observed in the acceleration response of the central cross-section soil,leading to the strongest seismic response at this point.However,the acceleration amplification factors of other points decrease with increasing buried depth.(4)The dynamic response of a point under the XZ bidirectional seismic wave is much higher than that under the X unidirectional seismic wave,especially when the seismic intensity is between 0.4g and 0.6g.Seismic waves with different loading directions diversely affect the seismic response at the invert of the overlapped tunnels.

关 键 词：立体交叉隧道 大型振动台试验 动力响应 加速度峰值 加速度放大系数 

分 类 号：U452.28[建筑科学—桥梁与隧道工程]