俯冲带板内地震的位移谱阻尼修正系数研究  

Study on damping correction factor for displacement spectra of subduction slab earthquakes

作　　者：张衡 朱敏[1] 杨新格 ZHANG Heng;ZHU Min;YANG Xinge(School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China)

机构地区：[1]西南交通大学土木工程学院,四川成都610031

出　　处：《地震工程与工程振动》2018年第6期202-213,共12页Earthquake Engineering and Engineering Dynamics

基　　金：国家自然科学基金项目(51578470)~~

摘　　要：为了建立一个用于调整设计反应谱的B_d模型,本文利用Zhao et al的场地分类方法,将KiK-net和K-NET地震数据库中4 695条M_w≥5.0的俯冲带板内地震动记录分成了四组,并对每组数据在36个谱周期、14个阻尼比水平下的位移谱阻尼修正系数B_d的几何均值进行了分析。阻尼比小于0.05时,B_d会随谱周期先增后减,在短周期内I类场地的B_d最大、IV类最小,在中长周期时,II类最小、IV类最大,阻尼比大于0.05时,具有相反变化规律。通过对不同场地间B_d的方差和均值进行F-检验和t-检验,本文证明了场地分类的必要性,基于最小二乘回归法,给出了B_d关于谱周期和阻尼比的表达式。为研究回归方程的残差组成,文中利用随机效应方法对残差进行了分解。结果表明:整体上震源效应产生的随机误差小于其他效应产生的随机误差,场地效应产生的随机误差小于路径效应产生的随机误差。位移谱阻尼修正系数还受到矩震级、震源深度和震源距的影响,本文模型暂未考虑这些因素。We divided 4695 strong-motion records from KiK-Net and K-Net in Japan into four groups according to the recording station site classes defined by the Zhao et al.(2006). These records are from subduction slab earthquakes. Spectra from each site class(SC) were computed at 36 spectral periods and 14 damping ratios, and the geometric mean spectrum from the two horizontal components was used to compute the damping correction factor(Bd) with respect to the spectra having a damping ratio of 0.05. Our results showed that Bd mainly depends on site class, damping ratio and spectral period. When damping ratio is less than 0.05, Bd increases with increasing spectral period at short periods and decreases with increasing periods at the other spectral periods. At short periods, Bd has the largest value for SCI sites and the smallest value for SCIV sites. At intermediate and long periods, Bd has the smallest value for SCII sites and the largest value for SCIV sites. When damping ratio is larger than 0.05, Bd varies with spectral periods in an opposite manner as to that for small damping ratios. Statistical tests suggest that the geometric mean values and the standard deviations for Bd differ significantly from one site class to another at many spectral periods, validating our approach using different models for different site classes. Based on statistical analyses, models for Bd are presented for four site classes as a function of spectral periods and damping ratio with a reasonably small standard deviation. In order to study the error sources, using a random effects model, the total standard deviations were separated into between-and within-event parts and the within-event parts were further divided into within-and between-site parts. Results show that source effects lead to the smallest standard deviation compared with the path and site effects. The damping correction factors also depend on earthquake magnitude, source depth and source distance. The objective of this study is to develop a damping correction facor for scaling a

关 键 词：阻尼修正系数 位移反应谱 场地类别 阻尼比 谱周期 俯冲带板内地震 

分 类 号：P631.443[天文地球—地质矿产勘探]