摘要
场地周期作为场地固有特性是评价场地条件的重要参数。本文在详细阐述场地周期基本概念的基础上将其区分为场地卓越周期和场地基本周期,并详细分析总结了这两种周期的不同确定方法。场地卓越周期是地震波在场地中传播幅值被明显放大频带对应的周期,主要是是利用地脉动或强震动记录通过频谱分析得出的,给出的是场地周期的范围,有时根据频谱曲线会无法识别场地卓越周期。场地基本周期是将场地假定为覆盖在均匀、各向同性线弹性基岩半空间上的水平成层均匀、各项同性的线弹性土层场地,无阻尼的情况下第一振型对应的周期。通过场地的物理参数(剪切波速或剪切模量,土层厚度和质量密度等)计算得出,计算方法包括解析法、数值法和简化法,实际应用中经常采用的方法是简化法。一般地,两种方法的确定结果不尽相同,在场地不太厚,场地土不太软的情况下,二者的确定结果相近。
As the inherent characteristic of the site, the site period is an important parameter to evaluate the site conditions.On the basis of elaborating the basic concept of site period, this paper divides the site period into site predominant period and fundamental period, and summarizes the different determination methods of these two periods in detail.Site predominant period is the period corresponding to the frequency band in which the amplitude of seismic wave propagation in the site is significantly amplified, It is mainly obtained through spectrum analysis by using microtremors or strong earthquake records, and the range of site predominant period is given. Sometimes site predominant period cannot be identified according to spectrum curve.The fundamental period of the site is assumed to be the period corresponding to the first vibration mode in the case of no damping.Through the calculation of the physical parameters of the site(shear wave velocity or shear modulus, soil thickness and mass density, etc.), the calculation methods include analytical method, numerical method and simplified method.Generally, the determination results of the two methods are not the same. Under the condition that the site is not too thick and the soil is not too soft, the determination results of the two methods are similar.
作者
华永超
齐文浩
薄景山
郑桐
HUA Yongchao;QI Wenhao;BO Jingshan;ZHENG Tong(Key Laboratory of Earthquake Engineering and Engineering Vibration,Institute of Engineering Mechanics,CEA,Harbin 150080,China;Department of Disaster Prevention Engineering,Institute of Disaster Prevention,Sanhe 065201,China)
出处
《地震工程与工程振动》
CSCD
北大核心
2020年第2期239-251,共13页
Earthquake Engineering and Engineering Dynamics
基金
中国地震局工程力学研究所基本科研业务费专项资助项目(2019C06)。
关键词
场地卓越周期
场地基本周期
地脉动
强震动记录
第一振型
site predominant period
site fundamental period
microtremors
strong earthquake record
the first vibration mode
