基于HHT地震动分量分离的长周期地震动界定方法  

Classification method for long period ground motions based on component decomposition with HHT

作　　者：李英民[1,2] 赵晨晓 谭潜[1] LI Yingmin;ZHAO Chenxiao;TAN Qian(School of Civil Engineering,Chongqing University,Chongqing 400045,China;MOE Key Lab of New Technology for Construction of Cities in Mountain Area,Chongqing 400045,China)

机构地区：[1]重庆大学土木工程学院,重庆400045 [2]山地城镇建设与新技术教育部重点实验室,重庆400045

出　　处：《振动与冲击》2018年第7期164-171,219,共9页Journal of Vibration and Shock

基　　金：国家自然科学基金面上项目(51478068;51478067)

摘　　要：长周期分量是地震动长周期特性的决定性成分,能反映长周期地震动的基本特性。基于HHT方法,提取加速度反应谱平均周期T_r≥2 s的IMF及残余分量重构并进行基线校正作为该地震动的长周期分量;通过长周期分量与原地震动的相关性分析及其在超高层建筑的结构响应中的影响验证了其界定长周期地震动的合理性。提出了基于长周期分量特性的界定指标LPGI,当LPGI>0.6时的地震动为长周期地震动;用长周期分量的归一化Hilbert累积能量曲线从5%增长至95%所经历的时间t_(90%)来表征长周期地震动的脉冲特性,从而区分远场类和谐长周期地震动和近断层脉冲性地震动这两类特殊长周期地震动;为长周期地震动的区分提供了较好的方法与参数指标。Long period component is a decisive one to reflect basic characteristics of long period ground motions(LPGMs).Based on Hilbert-Huang transform(HHT),in ground motion’s acceleration response spectrum,intrinsic mode functions(IMFs)with average period T r≥2.0 s and residual components were extracted to reconstruct a signal which was taken as the long period component of the original ground motion after baseline correction.The rationality of classifying a long period component was verified using the correlation analysis between the long period component and the original ground motion and effects of the long period component on structural responses of a super high-rise building.The long period ground motions indicator(LPGI)based on long period component characteristics was proposed,it was shown that the ground motion is LPGM when its LPGI>0.6.The time interval needed for the area between the normalized Hilbert accumulated energy curve of a long period component and time axis to increase from 5%to 95%was proposed to represent pulse characteristics of LPGM.Thus the two kinds of special LPGMs including far-field LPGMs and near-field ones were distinguished.The results provided a better method and a parametric indicator for distinguishing LPGMs.

关 键 词：HHT 平均周期 长周期分量 长周期地震动 界定方法 

分 类 号：P315.31[天文地球—地震学]