强地震动幅值谱随机涨落特征的研究

本文从工程应用的观点，将强地面运动幅值谱?Ａ（ｆ）│表示为强度受到调制的随机过程即│Ａ（ｆ）│＝│Ａ（ｆ）│〔１＋ｎ（ｆ）〕其中，│Ａ（ｆ）│为随频率变化的确定性函数亦是│Ａ（ｆ）│的均值，ｎ（ｆ）为均值为零的随机过程。在随机过程ｎ（ｆ）为各态历经的假定下，研究了ｎ（ｆ）的功率谱密度函数的特征及其衰减形式。根据地震学的有关理论，提出了用四个参数控制幅值谱的均值随频率变化的函数形式并对拟合这些参数的

STUDY ON RANDOM FLUCTUATION CHARACTERISTICS OF AMPLITUDE SPECTRA OF STRONG GROUND MOTION

For convenient engineering application this paper assumes that amplitude spectrum of strong ground motion is a random process with modulation intensity as follows where is a mean value of or a deterministic function that changes with frequen is a random process with zero mean value. Under the assumption that the random process is ergodic attenuation properties of power spectra density function of (f) have been studied in detail. According to theory of seismology we have used four parameters to control mean value function of amplitude spectrum that changes with frequency and discussed the principle of fitting these parameters. Using SMART-1 array data this paper has analyzed quantitatively amplitude spectra and their random disturbance properties of strong ground motion. These results indicate that random disturbance of amplitude spectra leads to variation of acceleration peak ranged from 3 percent to 12 percent but great variation of response spectra from 10 percent to 33 percent.