摘要
为研究黄土隧道洞口段坡-隧系统地震动力响应特征,开展了大型振动台模型试验,通过对坡-隧系统模型输入不同强度和方向的地震动分析,得出了峰值加速度(PGA)分布规律,并采用小波包分析得到了隧道与围岩的相互作用和坡-隧系统能量变化规律。结果表明:(1)随着台面输入地震动强度增加,隧道结构PGA相应增大,沿隧道方向拱顶加速度在洞口段有明显放大现象,一定距离后趋于稳定,而且拱顶PGA值始终大于仰拱处;(2)坡-隧系统洞口段坡面结构上同一测点相同工况下水平方向PGA明显大于竖直方向,并且同一工况下随着坡高增大各测点水平方向PGA呈现非线性增大趋势,但在坡顶处并未增大,反而变小;(3)能量分布图中仅汶川汤峪波呈现出“V”型分布,且在其水平向加载下隧道周围土体能量有很明显的“集聚效应”。试验结果有助于揭示黄土地区坡-隧系统在地震动力作用下的变形失稳机制,为交通隧道抗震设防和措施优化提供参考。
The shaking table model test was carried out to study the seismic response characteristic of loess tunnel portal section of the slope-tunnel system of loess tunnel.The response patterns of peak ground acceleration(PGA)is obtained through the analysis of slope tunnel system under different seismic input,and the method of wavelet packet energy analysis was used to obtain the interaction between the tunnel and the surrounding rock and the slope energy variation law of the model structure of the slope-tunnel system.The results show that:(1)With imported mesa vibration intensity increases,the tunnel structure PGA increases accordingly,and inverted arch and vault acceleration direction along the tunnel manifest in tunnel portal and stabilized after a certain distance,the PGA value at the vault crown is always bigger than that at inverted arch;(2)On the slope structure of loess tunnel system,the horizontal PGA is obviously bigger than the vertical one at the same measuring point,and the horizontal PGA shows a nonlinear increasing trend with the increase of the slope height in the same working condition;(3)In the energy distribution patterns,only the Wenchuan Tangyu wave shows a“V”shaped distribution,and the energy in the soil around the tunnel under the X direction of the Wenchuan wave has a significant“gathering effect”.The experimental results are helpful to reveal the mechanism of seismic deformation and failure of slope tunnel system in loess area,and provide reference for seismic fortification and measures optimization for transportation tunnels.
作者
艾胜军
梁庆国
赵涛
乔向进
王丽丽
周稳弟
AI Shengjun;LIANG Qingguo;ZHAO Tao;QIAO Xiangjin;WANG Lili;ZHOU Wendi(School of Civil Engineering,Lanzhou Jiaotong University,Lanzhou 730070,China;Key Laboratory of Road&Bridge and Underground Engineering of Gansu Province,Lanzhou Jiaotong University,Lanzhou 730070,China;College of Urban Rail Engineering,Shaaxi Railway Institute,Weinan 714000,China;China National Nuclear 404 Co.,Ltd.,Jiayuguan 735106,China;Key Laboratory of Loess Earthquake Engineering,Lanzhou Institute of Seismology,CEA,Lanzhou 730000,China)
出处
《地震工程与工程振动》
CSCD
北大核心
2020年第6期168-177,共10页
Earthquake Engineering and Engineering Dynamics
基金
国家自然科学基金项目(51968041,41562013)
兰州交通大学“百名青年优秀人才培养计划”
陕西省高校科协青年人才托举计划项目(20190706)
甘肃省科技计划项目(18YF1GA055)。
关键词
黄土隧道
坡隧系统
峰值加速度
振动台试验
小波包分析
loess tunnel
slope-tunnel system
peak ground acceleration
shaking table test
wavelet packet transform
