摘要
研究河谷场地地震效应对场地选址和抗震设计具有重要的指导意义。基于离心机振动台试验分析,研究了梯形河谷场地地震动响应规律。结果表明:基岩河谷场地对地震动有一定的放大效应,放大效应随着地形的变化而变化,但放大效应不显著,场地不同位置对反应谱的影响较小;基岩-土模型基岩面地震动放大倍数明显增大,不同输入地震动情况下放大倍数不同,各个场点对频段为0.5~2.5 s的地震动有明显的放大作用,对地震动放大频域范围明显加大,这与纯基岩场地的有明显的不同,虽然各个场点的反应谱形状有一定的差别,但是反应谱的平台值和特征周期相差不大;由于河谷场地地形效应,河谷场地地表峰值加速度随着地形的变化放大倍数随之变化,阶地级数越高放大倍数越大,谷底放大倍数最小,随着输入地震动强度的增加,阶地级数越高反应谱的平台值越高,特征周期越大。
Studying the seismic effects of valley site has critical guiding significance for site selection and aseismic design.Based on the analysis of centrifuge shaking table tests,the ground motion response pattern of the trapezoidal valley was studied.The results showed that there was a certain amplification effect of ground motion in the bedrock valley site.The amplification effect varied with the change of terrain,but the amplification effect was not significant.Different site locations had a small influence on the response spectrum.In the bedrock-overburden model,an obvious increase of the ground motion magnification was observed at the bedrock surface.Different magnifications were found under different input ground motions.The amplification effect of the ground motion was particularly evident on different sites when the frequency band was in the range of 0.5-2.5s.In this frequency band,the frequency range of ground motion amplification was increased significantly,which was different from the pure bedrock sites.In the case of the pure bedrock sites,although the shape of the response spectrum was somewhat different for individual sites,the plateau value and characteristic period of the response spectrum were similar.Due to the terrain effect of the valley site,the amplification factors of the peak surface acceleration of the valley site changed with the change of the terrain.The higher the terrace levels of the valley,the greater its magnification,and the amplification of valley bottom was the smallest.With the increase of the input ground motion intensity,the higher the terrace levels,the higher the plateau value,and the greater the characteristic period of the response spectrum.
作者
李平
张宇东
薄涛
辜俊儒
朱胜
LI Ping;ZHANG Yu-dong;BO Tao;GU Jun-ru;ZHU Sheng(School of Geological Engineering,Institute of Disaster Prevention,Sanhe,Hebei 065201,China;Key Laboratory of Earthquake Engineering and Engineering Vibration,Institute of Engineering Mechanics,China Earthquake Administration,Harbin,Heilongjiang 150080,China;Beijing Earthquake Agency,Beijing 100080,China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2020年第4期1270-1278,1286,共10页
Rock and Soil Mechanics
基金
国家自然科学基金青年基金项目(No.51508096)。
关键词
离心机振动台试验
河谷场地
地震动
抗震设计
centrifuge shaking table test
river valley site
ground motion
aseismic design
