摘要
土层结构对地表地震动具有重要影响,其中含软弱夹层场地对地表地震动的影响尤为显著。使用高岭土、膨润土和粉煤灰配制模型软土,构建具有软弱夹层场地的振动台试验模型,通过输入不同峰值加速度和频谱特性的地震动,探讨软弱夹层场地对地表地震动的影响。结果表明:(1)软弱夹层对地表地震动具有一定的减震作用。(2)在不同峰值和频谱特性的地震动作用下,软弱夹层的减震效果不同。当输入低频地震动时,随着其峰值加速度的增加,软弱夹层减震作用减弱;当输入高频地震动时,随着其峰值加速度的增加,软弱夹层减震作用增强,输入地震动频率越接近模型的自振频率,软弱夹层的减震作用越显著。(3)在同一峰值加速度地震动下,PGA放大系数随输入地震动频率增加呈减小趋势。(4)地表地震动反应谱幅值在高频段差异明显,在低频段相差较小,可见软弱夹层对高频分量减震效果显著,但对低频分量影响较小。
The soil layer structure has a significant influence on surface seismic motion.In particular,the influence of the site with a weak intercalated layer on the surface ground motion is especially remarkable.In this paper,we use kaolin,bentonite and quartz sand powder to formulate a model soft soil,and construct a shaking table test model of the site with weak intercalated layer.The influence of the site with a weak intercalated layer on surface ground motion is discussed by inputting ground motions with different peak acceleration and frequency.The results show that:(1)The weak intercalated layer has a certain shock absorption effect on the surface ground motion.(2)The shock absorption effect of the weak intercalated layer is different under inputting ground motions with different peak acceleration and frequency.When inputting low-frequency ground motion,the shock absorption effect of the weak intercalated layer is weakened with the increase of its peak acceleration;when inputting high-frequency ground motion,the shock absorption effect of the weak intercalated layer is strengthened with the increase of its peak acceleration,and the closer the input frequency of ground motion is to the natural frequency of the model,the more significant shock absorption effect of the weak intercalated layer is.(3)Under the same peak acceleration,the PGA amplification factor tends to decrease with the increase of the input ground motion frequency.(4)The difference in the amplitude of the surface ground motion response spectrum is obvious in the high-frequency band,and that is small in the low-frequency band,which shows that the weak intercalated layer has a significant shock absorption effect on the high-frequency component,but has a small effect on the low-frequency component.
作者
李平
李晨
陈钰鑫
LI Ping;LI Chen;CHEN Yuxin(Institute of Disaster Prevention,Sanhe 065201,China;Hebei Key Laboratory of Earthquake Disaster Prevention and Risk Assessment,Sanhe 065201,China)
出处
《防灾科技学院学报》
2025年第2期1-9,共9页
Journal of Institute of Disaster Prevention
基金
国家重点研发计划(2024YFC3017003)
中央高校基本科研业务专项(ZY20230207)。
关键词
软弱夹层
地表地震动
振动台
峰值加速度
反应谱
weak intercalated layer
surface ground motion
shaking table
peak ground acceleration
response spectrum
作者简介
李平(1981-),男,博士,教授,主要从事场地效应及岩土工程抗震方面的研究.
