【摘要】 2008年汶川MS8.0地震获得了大量的强震动记录,为研究反应谱特征参数衰减特性提供了重要的基础资料.本文对已知场地条件的174个台站的记录进行研究,计算其加速度反应谱并按照最小二乘分段拟合方法进行标定,进而拟合了反应谱平台值的衰减关系;对比分析了水平方向与竖直方向反应谱平台值的衰减特性,提出用"平台值的场地衰减影响系数"来定量研究不同场地类型对反应谱平台值的影响,用"衰减曲线下降速率"来定量分析不同衰减曲线的衰减速率.通过计算得出水平向Ⅰ,Ⅱ,Ⅲ类场地的平台值场地衰减影响系数平均值分别为0.535 8,1和1.579,且Ⅲ类场地的加速度平台值衰减曲线的衰减速率最小.更多还原

【Abstract】 After the 2008 Wenchuan MS8.0earthquake,a large volume of strong motion records were acquired,which provides important basic data for the study on attenuation characteristics of seismic response spectrum parameters.This paper calculates the acceleration response spectra of strong motion records from174 seismic stations with known site conditions.The spectra are calibrated via piecewise fitting with the least-squares method in order to fit the attenuation relationships of a response spectrum platform value.This paper also comparatively analyzes the attenuation characteristics of both vertical and horizontal response spectrum platform values so as to demonstrate how the quantitative study of site condition affects response spectrum platform values by means of the site attenuation influence coefficient of platform value.It also quantitatively analyzes the attenuation rates of different attenuation curves by means of their descending rates. The calculation results show that the site attenuation influence coefficients of horizontal platform value has an average value that is different for the three site types.The value for site typeⅠ is 0.535 8,typeⅡ is 1;and typeⅢ is 1.579,which is the minimum attenuation rate of the platform in all site types.更多还原