【摘要】 选择国家强震动台网中心发布的2008年5月12日汶川地震四川、甘肃、陕西等地台站中的94组加速度记录进行了处理,提取了一些主要地震动参数,应用统计分析方法重点对地震动竖向与水平峰值加速度比、竖向与水平加速度反应谱及竖向与水平卓越周期比等进行了研究。结果表明:竖向与水平峰值加速度比的平均值为0.58,但约30%台站的峰值加速度比大于2/3;竖向与水平峰值加速度比随震中距的增大减小,近震区该比值离散性较大,场地条件对该比值也有较大的影响;在周期0~6s内竖向与水平加速度反应谱比曲线总体呈马鞍形;不同的周期段,竖向加速度反应谱和水平加速度反应谱的谱形有较大差异,相比水平加速度反应谱,竖向加速度反应谱偏"瘦";除少数台站外,绝大部分台站竖向与水平卓越周期比均小于1.0,该比值随震中距的增大而增大,并逐渐趋于平缓。上述研究结果可以为时程分析选取竖向地震动输入提供参考。更多还原

【Abstract】 94 suites of acceleration records from the stations in Sichuan,Gansu and Shaanxi provinces during the Wenchuan earthquake of May 12,2008,which were released by China Strong Motion Networks Center,were selected to the process for extracting some essential ground motion parameters.The ratios of vertical to horizontal peak ground accelerations,the acceleration response spectra and predominant period were mainly investigated with the method of statistical analysis.The results indicated that the average ratio of vertical to horizontal peak ground motion is 0.58,and the ratios of more than 30% stations are greater than 2/3.This ratio decreases with the increasing epicentral distance and it is much discrete in the near-fault region.Furthermore,site condition also influences this ratio.The curve of vertical to horizontal acceleration response spectrum ratios with periods from 0 to 6 second appears to be saddle-shaped generally.The shapes of vertical and horizontal acceleration response spectrum vary within different period ranges.And vertical acceleration response spectrum looks thin comparing to the horizontal counterpart.Except several stations,the ratio between vertical to horizontal predominant periods is less than 1.0.This ratio increases with the increasing epicentral distance and becomes smooth gradually.The study results can provide a reference for choosing the vertical ground motion input during a time history analysis.更多还原