川滇甘陕地区地震的加速度峰值比和竖向反应谱的统计分析

Statistical analysis of peak acceleration ratio and vertical response spectrum of earthquakes in Sichuan Yunnan Gansu Shaanxi

本文以国内川滇甘陕地区263个有详细场地资料的强震台站获得的802组地震动加速度记录为基础,研究了该地区加速度峰值比的总体分布特征,分别探讨了震中距和震级对加速度峰值比的影响特征,按照水平反应谱的标定方法对竖向反应谱进行标定并对其进行了统计分析。统计分析结果显示:竖向与水平向加速度峰值比的概率分布总体服从极值Ⅱ型分布,加速度峰值比均值为0.6,加速度峰值比≤0.65的累积频率为64%;Ⅱ类场地的加速度峰值比随震中距增大而减小;大震近场的加速度峰值比基本上远高于0.65;最后本文给出了不同场地类别下竖向反应谱特征参数,并与水平向反应谱特征参数进行了比较。

Based on 802 sets of ground motion acceleration records obtained from 263 stations with detailed site data in Sichuan,Yunnan,Gansu and Shaanxi provinces,the overall distribution characteristics of peak acceleration ratio in this area are studied.The effects of epicenter distance and magnitude on the peak acceleration ratio are discussed.According to the calibration method of horizontal response spectrum,the vertical response spectrum was calibrated and analyzed statistically.The results show that the probability distribution of the ratio of vertical and horizontal acceleration peak value follows extreme value type II distribution,the average value of peak acceleration ratio is 0.6,and the cumulative frequency of peak acceleration ratio≤0.65 is 64%.For class II site,the peak acceleration ratio decreases with the increase of epicentral distance.The peak acceleration ratio in the near field of large earthquakes is much higher than 0.65.The characteristic parameters of vertical response spectrum under different site types are given and compared with those of horizontal response spectrum.