用震级和距离参数修正土层反应的等效线性化方法  

Modify equivalent linear method of finding soil seismic response with magnitude and distance parameters

作　　者：沈建文[1] 刘峥[1] 石树中 

机构地区：[1]上海市地震局,中国上海200062 [2]浙江省地震局,中国杭州310013

出　　处：《地震学报》2010年第4期466-475,共10页Acta Seismologica Sinica

基　　金：浙江省重点科研社会发展项目(2005C23075)资助

摘　　要：传统等效线性化波动法主要的缺陷之一,是当基岩输入地震动较强时,高频段算得的频响放大倍率比实际场地的实测结果明显偏低.该缺陷可能导致低估重大工程的设计地震动参数的严重后果,因而是亟待解决的重要问题.本文认为,现行基于土的剪切模量和阻尼比的频率相关性修正等效剪应变的做法有其合理性,但不便应用并可能具有较大的不确定性;由于震级可以影响地震动的频谱特征,通过震级调整等效剪应变的做法也可视为按照频率调整等效剪应变.由于距离与震级一样也可以影响地震动的频谱特征,本文提出通过震级M和距离R参数修正等效线性化的方法EQLM(M,R),并用算例说明,等效线性化方法的上述缺陷可以通过本文提出的EQLM(M,R)方法得到一定程度的改善.One of important shortcomings of the traditional equivalent linear method （EQLM）is that for large input motions the magnification of high frequency components calculated is obviously lower than that observed.The defect may lead to a serious result of underestimating design ground motion parameters for key projects.So this important issue needs to be solved.Although it is reasonable to improve EQLM by using frequency-dependent modules and damping ratios,it is not convenient to use and has great uncertainties.This article points out that,because magnitudes can affect spectra of ground motion,the method to improve EQLM by adjusting equivalent shear strain based on magnitudes may also be regarded as frequency-dependent.Since distance can also affect the spectra,we suggest a method EQLM（M,R） to improve EQLM by the parameters of magnitudes and distances.An example of EQLM（M,R） is given to show that the above-mentioned shortcoming of EQLM can be resolved to some extent.

关 键 词：土层地震反应 等效剪应变 等效线性化方法 频率相关模量和阻尼比 

分 类 号：P315.9[天文地球—地震学]