摘要
结合实际工程,在模型试验结果和数值模拟结果验证合理的基础上,以地震作用下浅埋偏压黄土双连拱隧道坡—隧系统动力响应特性作为主要研究目标,选取波形为EL波模拟地震作用,建立有限元三维模型,分析了隧道修建前后坡体动力响应差异和不同地震动强度下坡隧系统的动力响应规律。结果表明:边坡加速度放大系数在陡坡段呈现出明显的非线性变化趋势,隧道修建完成后,地震动在陡坡段引起较大响应,而在缓坡段出现一定的加速度饱和现象;隧道的存在对附近围岩有加固效应,而对坡面有一定的劣化效应;地震动引起台阶状护坡交界处以及距坡脚2/3处附近产生较大的剪应变,且这种响应规律随着地震动强度的增加而显著;地震动强度增加时,岩土—结构相互作用增强,浅埋侧隧道拱顶和右拱腰受力更为不利;0.1~6.25 Hz(低频波)的能量占比测点变化规律与加速度沿测点变化规律一致,是引起土体响应和破坏的主要因素;随着高程增加,陡坡段低频波能量占比高,在缓坡段有减小趋势,而高频波变化趋势与低频波变化趋势相反。本研究对黄土地区软弱围岩的双连拱隧道及边坡抗震设计具有一定的借鉴意义。
In this paper,combined with practical projects,on the basis of model test and numerical simulation verification,the dynamic response characteristics of double-arch slope tunnel system in shallowburied biased loess under earthquake action is taken as the main research objective.The waveform of EL wave is selected to simulate earthquake action,and three-dimensional finite element model is established to analyze the difference of slope dynamic response before and after tunnel construction and the dynamic response law of tunnel system under different ground motion intensity.The results show that the slope acceleration amplification coefficient presents an obvious nonlinear change trend in the steep slope section.After the completion of tunnel construction,the ground motion causes a large response in the steep slope section,while the acceleration saturation phenomenon appears in the gentle slope section.The tunnel has reinforcement effect on surrounding rock,and deterioration effect on slope.The shear strain at the junction of stepped slope protection and near 2/3of the slope foot is relatively large due to ground motion,and the response law is significant with the increase of ground motion intensity.With the increase of ground motion intensity,the effect of rock-soil structure is enhanced,and the stress of shallow buried tunnel vault and right arch waist is more unfavorable.The energy ratio of 0.1-6.25Hz(low frequency wave)is consistent with the acceleration along the measuring point,which is the main factor causing soil response and failure.With the increase of elevation,the low-frequency wave energy proportion increases in steep slope section,and decreases in gentle slope section,while the change trend of high-frequency wave is opposite to that of low-frequency wave.This study has certain reference significance for seismic design of double arch tunnel and slope in soft surrounding rock in loess area.
作者
张建
郭子润
李超杰
岳建平
陈星宇
ZHANG Jian;GUO Zi-run;LI Chao-jie;YUE Jian-ping;CHEN Xing-yu(Poly Changda Engineering Co.Ltd.,Guangzhou 511431,China;School of Civil Engineering,Lanzhou Jiaotong University,Lanzhou 730070,China)
出处
《公路》
北大核心
2024年第5期457-465,共9页
Highway
基金
中国博士后科学基金项目,项目编号2021M693843。
关键词
连拱隧道
黄土边坡
动力响应特征
偏压特征
小波包分析
multi-arch tunnel
loess slope
dynamic response characteristics
bias characteristics
wavelet packet analysis
