偏压条件下特大断面隧道地震动态响应的数值模拟研究  

Seismic Responses of Large-section Tunnel with Unsymmetrical Loading Based on Numerical Simulations

作　　者：关振长[1] 朱凌枫 乔梁 唐勇三 GUAN Zhenchang;ZHU Lingfeng;QIAO Liang;TANG Yongsan(College of Civil Engineering,Fuzhou University,Fuzhou 350116,China;Haixia(Fujian)Transportation Engineering Design Co.,Ltd.,Fuzhou 350004,China;Pingtan Comprehensive Experimental Area Transport Investment Group Co.,Ltd.,Pingtan 350400,China)

机构地区：[1]福州大学土木工程学院,福建福州350116 [2]海峡(福建)交通工程设计有限公司,福建福州350004 [3]平潭综合实验区交通投资集团有限公司,中国平潭350400

出　　处：《应用基础与工程科学学报》2021年第4期927-938,共12页Journal of Basic Science and Engineering

基　　金：国家自然科学基金项目(51678155);福建省交通运输科技项目(201919)。

摘　　要：以福州市二环路金鸡山隧道为工程背景,利用数值模拟方法研究偏压条件下特大断面隧道的地震动态响应(包括地层加速度及衬砌接触压力的动态响应),并与已完成的振动台模型试验结果相互对比验证.数值模拟结果表明:地层各测点的PHA放大系数,沿地层中轴面及衬砌边缘随高程呈对数型增长,沿临空侧坡面随高程呈指数型增长;中上部地层各测点的PHA放大系数,随地震动幅值增大呈近似线性减小趋势,而下部地层各测点的PHA放大系数则基本不变.上述数值模拟结果所表现出的高程效应,与模型试验结果基本一致.另一方面,由于地形偏压影响,静止工况下隧道衬砌上的接触压力表现出一定的偏压效应;随着地震动幅值增大,其偏压效应被进一步放大,大震幅工况下靠山侧衬砌所承担的最大接触压力约为静止工况的3倍,最小接触压力几乎为零(即衬砌与围岩完全脱空).但相比于模型试验,本次数值模拟中的衬砌始终设置为弹性状态,可能高估了其所承担的接触压力.Based on the Jinjishan tunnel in Fuhou 2 nd ring road, the seismic responses of large section tunnel under unsymmetrical loading with shallow cover are well studied through numerical simulations.The responses of ground acceleration and the lining contact pressure are further compared with the test results from shaking table experiment.The amplification coefficients of peak horizontal acceleration(PHA) increase logarithmically with the elevation along ground central axis plane, and increase exponentially with the elevation along slope free face.With the increasing of peak ground motion, the PHA amplification coefficients at the lower part remain unchanged, while the PHA amplification coefficients at the middle and upper part tend to decrease linearly.The elevation effect reflected by numerical simulations coincides with those results from shaking table tests.The distribution of contact pressure along lining perimeter is unsymmetrical due to the terrain slope.The unsymmetrical loading effect is intensified with the increasing of peak ground motion.On the scenario of large ground motion excitation, the maximum lining contact pressure against the slope reaches 3 times as the static condition, while the minimum lining contact pressure towards the slope reduces to zero almost.Comparing to the test result from shaking table test, however, the lining contact pressure from numerical simulations may be over-estimated due to the elasticity assumption of lining structure.

关 键 词：特大断面隧道 地形偏压 地震动态响应 振动台模型试验 数值模拟 

分 类 号：U41[交通运输工程—道路与铁道工程]