基于相位差谱的时─频非平稳人造地震动的生成

本文首先考察了地震动加速度时程在时域和频域上的非平稳性，通过实例分析说明地震动加速度时程 的非平稳性不能由相位谱的概率分布唯一决定，进而阐明了相位差谱是影响地震动非平稳的决定性因素。经 统计检验确定了脉动相位差的概率分布模型，利用相位差谱的数字特征与地震特性参数之间的统计关系，给 出了基于相位差谱的地震动时程生成方法。最后，通过对计算实例的分析，证实了此方法能够反映并模拟实 际地震动的时─频非平稳性。

Generation of ground motion non-stationary both in time and fequency domains based on phase difference spectrum

The nonstationarity of earthquake ground motions both in time and frequency domains is studied by using window-moving method. It is shown that the nonstationarity is not controlled by phase angle spectrum, but by the phase difference spectrum defiined by Ohsaki. The statistical characteristics and probability distribution of the phase difference spectrum are dis- cussed. Then the ground motions non-stationary both in time and frequency domains are gener- ated based on the results about phase difference spectrum. Numerical examples show that the arti- ficial ground motions have the same time-frequency nonstationarity as the actual earthquake ground motions.