场地地震反应的特征线解与等效线性化解对比研究

Comparison Study on Results of Site Seismic Response between Characteristic-difference Method and Equivalent Linear Method

研究了响蹚(Ⅱ类)、盐城(Ⅳ类)、CHBH06(Ⅲ类)3种不同类别的场地在地震动作用下特征线差分计算结果与等效线性化法计算结果的差异性。在响蹚场地(Ⅱ类)下,随输入地震动峰值增加,特征线法计算的峰值加速度逐渐增加,反应谱曲线规律性递增;等效法计算峰值加速度先减小后增加,反应谱曲线在较大输入时逐渐递增。在盐城场地(Ⅳ类)下,特征线法计算的峰值加速度均比等效法的计算值稍大,反应谱平台宽度较等效法反应谱平台宽度宽。在KIK-net的CHBH06场地(Ⅲ类)中,将两种方法的计算结果与实际记录对比,结果表明:特征线法时程的傅里叶谱频带宽度与实际记录接近,加速度反应谱与实际记录的加速度反应谱较等效法加速度反应谱接近。通过对比分析,以期促进特征线差分方法的应用。

This paper studied the difference between the results computed from the characteristic-difference method and the equivalent linear method for three typical models including Xiangtang,Yancheng and CHBH06 sites. As the input peak acceleration increased in the Xiangtang site(classⅡ),the PGA(peak ground acceleration)calculated by the characteristic-difference method became larger gradually,while the PGA by the equivalent linear method decreased firstly and then increased.The response spectrum curves rose regularly for the characteristic-difference method,but didn’t increase till the input excitation was large enough for the equivalent linear method. In the Yancheng site(class Ⅳ),the PGA of the characteristic-difference method was larger than that of the equivalent linear method,and the platform of the response spectrum was wider than the one of the equivalent linear method. By comparing the calculated results with the earthquake record in the KIK-net CHBH06 site(classⅢ),the frequency band and response spectrum curve calculated by the characteristic-difference method were both closer to those of the actual record. The characteristic-difference method could be applied more widely through this analysis.