国际上两种典型土层地震反应分析程序对比研究

Contrasting study between two international typical soil layers seismic response analysis programs

土层地震反应分析方法分为频域与时域两大类,目前国际上最好的一维程序为SHAKE2000与DEEPSOIL,但二者的适用性和比较情况尚不得知。构造了符合我国规范的4种类别场地,对14个场地在3条地震动输入和3个烈度下总共82组工况进行对比计算,研究二者计算出的地表峰值加速度、反应谱和剪应变的异同。结果表明:二者差异大小与场地类别、输入PGA和输入地震动的频率分布有关,其中场地类别起主要作用,其他因素影响较小;只有在Ⅰ类场地下二者差异可忽略,其他类别场地存在差异,深软场地差异十分显著;虽然DEEPSOIL在计算反应谱高频部分表现优于SHAKE2000,但无论地表加速度峰值还是整体反应谱都要逊于后者,特别是对Ⅲ类场地和Ⅳ类场地情况;DEEPSOIL计算得到的土体剪应变普遍大于SHAKE2000,在软土场地表现十分显著,很多工况结果达到了不合理的程度,这应是其表现逊色的原因;在Ⅲ类和Ⅳ类场地下,两程序很多计算结果与现有认识相差很大。其结果为了解掌握土层地震反应分析方法的国际现有水平及今后方法改进提供了一定基础。

Methods of soil layers seismic response analysis are divided into frequency domain methods and time do- main methods. Nowadays, the best two analysis programs at the international level are SHAKE2000 and DEEP- SOIL, but the applicability and comparison between them are still confused. The article builds 4 classes of site up to GB50011 -2010, and compares 82 conditions which are composed by 14 sites and 3 seismic inputs （3 intensi- ty）, to discuss the differences in PGA, response spectrum and soil shear strain which are obtained by the two pro- grams. The results show as follows： these differences relate to the class of the site, seismic input and frequency dis- tribution, the class of site influences the difference most ; the difference can be negligible in class I , and the con- ditions in the other three classes show exceptions exist, especially in deep soft sites; the response spectrum got by DEEPSOIL is better than SHAKE2000 in the part of high - frequency, but performs worse in all three aspects than SHAKE2000, especially in high intensity class Ⅲ and all the sites in class Ⅳ; the soil shear strain got by DEEP-SOIL are generally greater than SHAKE2000, this shows apparent evidences in deep soft sites and be illogical in many conditions, this perhaps can be the reason why DEEPSOIL fades next to SHAKE2000; in class Ⅲ and Ⅳ, the results got by the two programs are greatly different with the existing knowledge. The results in this article can help us to grasp the internationally developmental level about the soil layers seismic response analysis and provide a foundation for the future program improvement.