地震动统一时频谱特性及其在人工合成中的应用  

Characteristics on unified time-frequency spectrum and application in ground motion simulation

作　　者：何浩祥[1,2] 闫维明[1,2] 韩恩圳[1] 

机构地区：[1]北京工业大学工程抗震与结构诊治北京市重点实验室,北京100124 [2]首都世界城市顺畅交通北京市协同创新中心,北京100124

出　　处：《振动工程学报》2016年第2期314-323,共10页Journal of Vibration Engineering

基　　金：国家自然科学基金资助项目(51108009;51378039);高等学校博士学科点专项科研基金资助项目(20111103120022)

摘　　要：传统地震动时域或频域理论模型不能充分反映地震动时频域的非平稳性。利用现代信号分析方法可以获得非平稳时变功率谱及演变谱,但缺乏精度评价标准。在理论和计算分析的基础上,确认小波包分解方法是建立时变功率谱的有效工具,并依据时频边缘条件提出时频谱分析精度评价标准。在地震动时频特征统计分析的基础上,认为地震动时频谱由多峰平滑谱和非平稳噪声谱两部分构成。分别建立由多峰平滑功率谱和非高斯频域噪声谱构成的地震动频域谱模型以及由多峰平滑时域能量谱模型和非高斯时域噪声谱模型构成的地震动时域谱模型。由此形成的时频谱模型在时频特性表征、函数表达、精度及多维分析等方面均有较强的统一性。依据统一时频谱进行调整或人工合成的地震动具有良好的精度和强非平稳性。Traditional ground motion theoretical models in time domain or frequency domain can＇t fully represent the nonstationarity. The time-varying power spectrum or evolutionary spectrum for ground motion can be calculated by the modern signal analysis methods. However, the corresponding accuracy evaluation criterion is inadequate at present. The wavelet packet decomposition method is verified as an efficient tool in establishing time-varying power spectrum on the basis of theoretical and computational analysis. The accuracy evaluation criterion is presented based on the marginal condition in time-frequency domain. The time-frequency characteristics in ground motions are studied on the basis of signal process and statistical analysis, and the time-frequency spectrum are resolved into the multi-peak smooth spectrum and the non-stationary noise spectrum. The frequency domain spectrum model which includes multi-peak smooth power spectrum and non-Gaussian noise spectrum in frequency domain is established. The time domain spectrum model which includes multi-peak smooth energy spectrum and non- Gaussian noise spectrum in time domain is established. The time-frequency spectrum embodies the unity in the aspects such as characteristics both in time domain and frequency domain, functions expression, accuracy and multidimensional analysis of ground motion. The good precision and strong nonstationarity can be obtained if the natural earthquake wave is adjusted or the artificial ground motion is generated according to the unified time-frequency spectrum.

关 键 词：地震动 功率谱 强度包络 时频分析 人工地震动合成 

分 类 号：P315.9[天文地球—地震学] O324[天文地球—固体地球物理学]