等效线性场地响应程序对比研究

A Comparative Study of Different Equivalent Linear Analysis Programs

为了评价4种等效线性场地响应软件的适用性,选取深厚场地作为研究对象,将基岩地震波作为地震输入,根据土层剪切波波速和容重确定初始剪切模量并设置对应的模量衰减和阻尼比曲线,分别用SHAKE 2000、 DEEPSOIL、EERA和Strata 4种等效线性场地响应程序计算得到地表的加速度时程及相应的加速度反应谱和傅里叶幅值谱\,场地的最大剪应变和峰值加速度随深度的变化曲线。计算结果表明,由4种场地响应软件得到的地表加速度时程对应的加速度反应谱和傅里叶幅值谱一致,由于土层划分方式不同,Strata软件得到的峰值加速度和最大剪应变深度曲线不同。总结4种软件的不同,DEEPSOIL可以较全面考虑土的动力特性,Strata提供随机振动理论进行场地响应分析并可以考虑土层参数的变异性。

In this paper,to evaluate the applicability of four equivalent linear analysis programs,i.e.,SHAKE 2000,DEEPSOIL,EERA,and Strata,the bedrock seismic wave was chosen as the input motion on a deep site.The initial shear modulus was determined according to the shear wave velocity and density of the soils,and the corresponding modulus decay curves and damping ratio curves were assigned.Surface acceleration time-histories,the corresponding acceleration response spectra,and the Fourier amplitude spectra were obtained by using the four programs.In addition,the maximum shear strain and peak ground acceleration vs.depth for the site were plotted.The results showed that the acceleration response spectra and the Fourier amplitude spectra obtained by the four programs were identical.The plots of maximum shear strain and peak ground acceleration vs.depth obtained by program Strata were different from those of the other three programs due to different division of soil layers.The differences among the four programs were summarized as well.The dynamic properties of soil can be comprehensively considered using DEEPSOIL with more formulas,and the random vibration theory proposed by Strata could be used for equivalent linear analysis.