相位差谱的分布特征和人造地震动

DISTRIBUTION CHARACTERISTIC OF PHASE DIFFERENCE SPECTRUM AND ARTIFICIAL ACCELEROGRAM

本文进行了地震加速度记录相位差谱的计算分析。文中指出,强震加速度时程的相位差分布符合对数正态分布,用该分布产生的随相角在合成人造地震动时程时并不需要叠加强度包络函数,所得人造地震动与实际记录十分相近,从而为合成频率含量和强度两者均为非平稳的人造地震动提供了一个实用性较强的方法。本文将对数正态分布相位差谱与正态分布相位差谱生成的人造地震动分别与实际记录进行了比较,结果表明用对数正态分布相位差谱合成的人造波与实际地震动吻合得更好。

According to the results of the phase difference spectrum of the actual accelerograms calculated in this paper, we have recognized that the phase difference distribution of strong earthquake accelerogram possesses characteristic of logarithmic normal distribution. When using the random phase angles with this kind of distribution, the artificial accelerogram generated without envelope function is close to the real record. So the practical method generating the artificial accelerogram with the frequency content and the intensity which are both non-stationary is afforded. By making a comparison between the artificial accelerogram with phase difference spectrum of logarithmic normal distribution characteristic and the one of normal distribution, we have verified that the artificial accelerogram generated with the phase difference spectrum of logarithmic normal distribution will best reflect the variation in the frequency and the intensity of the real accelerogram.