考虑地震时程的加筋土挡土墙动力分析  

Dynamic analysis of reinforced soil retaining walls considering time history of seismic acceleration

作　　者：汪益敏[1] 张晖[1] 黎寰[1] 陈页开[1] 

机构地区：[1]华南理工大学土木与交通学院亚热带建筑科学国家重点实验室,广州510640

出　　处：《振动与冲击》2013年第24期187-191,197,共6页Journal of Vibration and Shock

基　　金：国家自然科学基金项目(50808086);亚热带建筑科学国家重点实验室项目(2010ZC15)

摘　　要：针对我国加筋土挡土墙设计中对于地震时程对加筋土挡墙的动力响应认识模糊的问题,基于有限差分数值分析软件FLAC,对一座高6 m的土工格栅加筋土挡土墙进行了数值模拟,填土采用莫尔-库伦本构模型,土工格栅采用FLAC软件自带的Cable单元模拟,数值分析模型采用加拿大皇家军事学院的加筋土挡土墙振动台试验进行了验证,模拟分析时考虑了地震持续时间、地震波和地震峰值加速度的影响。数值计算结果对比了我国现行《公路加筋土工程设计规范》和美国FHWA设计规范的计算结果,研究表明:加筋挡土墙的土工格栅拉力和面板侧向位移随着地震持续时间的增加而增大,地震时程对加筋土挡土墙的受力和变形有较大的影响。地震加速度沿挡土墙高度有明显的放大效应,随着挡土墙高度增加,水平加速度的放大倍数逐渐增大。对于高度比较大的加筋挡土墙,传统的拟静力设计法采用单一地震系数的做法还有欠合理性,地震时程的影响应该在设计中得到充分重视。In order to study the dynamic responses of geosynthetic-reinforced retaining soil wall considering seismic time history, a finite difference numerical model of a 6m high geogrid reinforced soil retaining wall was built based on the software FLAC. The soil was modeled using Mohr-Coulomb constitutive model and the reinforcement geogrid was simulated using the Cable unit provided by the software FLAC. The rationality of the numerical model was verified with shaking table tests conducted at Royal Military College of Canada. The effects of persisting time of seismic accelation, seismic wave and peak seismic accelerations were considered. The numerical simulation results were compared with those obtained with the current Chinese Specifications for Design of Highway Reinforced Earth Engineering and with the FHWA design guidelines of us, respectively. The results showed that the remarkable effects of the seismic accelerating persisting time can increase tension force of the geogrid-reinforcement and lateral displacement of the retaining wall; seismic acceleration along the height of the reinforced retaining wall has an obvious amplifying effect; so the traditional quasi-static seismic design method only using a single seismic coefficient may be lack of rationality for the reinforced soil retaining wall with larger height, the influence of time history of seismic acceleration should be fully paid attention to in designs.

关 键 词：地震时程 加筋土挡土墙 数值模拟 FLAC 

分 类 号：TU472.34[建筑科学—结构工程]