摘要
建设场地的地震动一般用峰值、频谱、持时来描述,用既有方法确定的地震动可靠性难以检验。利用长宁地震中一个已知场地遭遇9次地震的记录作验证尝试,通过傅里叶谱、反应谱和谱比分析方法探讨记录所反映出的卓越周期的一致性。分析结果表明:东西向反应谱卓越周期平均值为0.21 s,南北向卓越周期平均值为0.18 s,竖向卓越周期平均值为0.11 s,这三个卓越周期值离散性都很小。场地勘察显示覆盖层厚度19.5 m,等效剪切波速197 m/s,场地特征周期为0.40 s。实际记录反映的卓越周期与勘察方法计算值相差一倍。用地震记录做谱比时,N/V(南北向)卓越周期为0.30~0.37 s,平均值为0.33 s。E/V(东西向)卓越周期为0.18~0.48 s,平均值为0.26 s。分析认为,场地卓越周期与个性化的地震输入密切相关。
The ground motion of construction site is generally described by peak value,spectrum and duration.The reliability of ground motion determined by existing methods is difficult to test. In this paper,the records of 9earthquakes in a known site during the Changning earthquake are used to verify the results. The consistency of the predominant period reflected by the records is discussed by means of Fourier spectrum,response spectrum and spectral ratio. The results show that the average value of the predominant period of east-west response spectrum is0.21 s,the average value of the predominant period of north-south predominant period is 0.18 s,and the average value of vertical predominant period is 0.11 s. The dispersion of these three predominant period values is very small.The site survey shows that the thickness of overburden is 19.5 m,the equivalent shear wave velocity is 197 m/s,and the site characteristic period is 0.40 s. The predominant period reflected by actual record is less than half of the calculated value of survey method. When seismic records are used for spectral ratio,the predominant period of N/V spectral ratio ranges from 0.30 s to 0.37 s,with an average of 0.33 s. The E/V predominant period ranges from 0.18s to 0.48 s, with an average value of 0.26 s, which is also close to the survey results. Overall, the site predominant period is closely related to personalized seismic input.
作者
江鹏
郭迅
何福
陈波
JIANG Peng;GUO Xun;HE Fu;CHEN Bo(Sichuan Earthquake Agency,Chengdu 610041,China;Key Laboratory of Building Collapse Mechanism and Defense,China Earthquake Administration,Institute of Disaster Prevention,Sanhe 065201,China)
出处
《华南地震》
2022年第3期29-35,共7页
South China Journal of Seismology
基金
国家重点研发计划项目(2018YFC1504302-3、 2016YEE0205100)。
关键词
长宁地震
场地
卓越周期
地震记录
一致性
Changning earthquake
Site
Predominant period
Seismic records
Consistency
