基于等效线性化方法的一维土层地震反应通用计算程序对比

Comparison of General Calculation Programs for One-dimensional Site Seismic Response Based on Equivalent Linearization Method

基于等效线性化的一维土层地震反应计算是目前国内外普遍采用的方法,国外的SHAKE91、DEEPSOIL和我国的LSSRLI-1即是根据这一方法编制的通用计算程序。本文采用这3个程序进行了不同地震波、不同输入地震动幅值下不同场地类型的土层地震反应计算,并对三者的结果进行了全面的比较分析。结果表明:(1)SHAKE91和DEEPSOIL程序的计算结果完全相同;(2)当土层最大剪应变均采用时域计算时,LSSRLI-1程序的计算结果与SHAKE91和DEEPSOIL程序基本相同,但有微小差别,其原因是:在基于等效剪应变通过离散形式的剪切模量和阻尼比随等效剪应变变化的关系曲线确定等效剪切模量和阻尼比时,DEEPSOIL和SHAKE91采用的插值方法与LSSRLI-1不同;(3)当LSSRLI-1程序采用频域经验关系计算土层最大剪应变时,特别是在强地震动输入下得到的土层地表加速度峰值和加速度反应谱与另外两个程序的计算结果有差别,且土层最大剪应变随着输入加速度的增大出现较大的差别。因此,本文建议:当采用LSSRLI-1程序计算土层地震响应时,应使用程序中的时域解方法代替以往默认的频域经验关系方法。

The method of one-dimensional site seismic response analysis based on equivalent linear analysis is widely used at home and abroad. For example, SHAKE91, DEEPSOIL and LSSRLI-1 are general calculation programs in abroad based on this method. In this paper, we compared and analyzed the results of site seismic response calculated by the three general calculation programs under different input earthquakes, different seismic amplitude values and different types of site layer. The results show that： （1）The SHAKE91 and DEEPSOIL basically produces the same results. （2）When the maximum shear strain of layer is calculated in time domain, the calculation results of LSSRLI-1 are almost identical with those of SHAKE91 and DEEPSOIL, but with slight differences. The reason is that the interpolation method, based on the equivalent shear strain through the relationship of the discrete form of shear modulus and damping ratio with equivalent shear strain to determine the equivalent shear modulus and damping ratio, used in DEEPSOIL and SHAKE91 is different from that of LSSRLI-1. （3）When the frequency domain empirical relationship is used to calculate the maximum shear strain of soil in LSSRLI-1, under strong input ground motions, the calculation peak acceleration and ground acceleration response spectra of the soil are different from those of the other two programs, and the maximum shear strains of layers calculated by LSSRLI-1 and the other two programs are greatly different with the increase of input acceleration. Therefore, when soil seismic response analysis is performed using LSSRLI-1, we suggested that the method of time domain should be used instead of the method of the default frequency domain empirical relationship.