【摘要】 地表设计谱可以直接由抗震设计规范确定,而基岩设计谱主要通过专门的地震危险性分析获得。地震危险性分析方法会受到潜在震源区划分、地震活动性参数、基岩地震动衰减关系等诸多环节的影响,且该方法未考虑基岩上覆场地的场地条件,由此获得的基岩设计谱与规范确定的地表设计谱常常并不协调。本文针对基岩设计谱确定困难这一问题,提出了工程场地基岩设计谱反演的一个方法。基于一维层状场地波动理论,利用等效线性化法考虑场地土的非线性,通过地表设计谱反演得到基岩设计谱。土层等效剪应变取各样本等效剪应变的平均值。该方法得到的基岩设计谱符合上覆场地的非线性动力特性,具有一定的工程应用价值。更多还原

【Abstract】 Surface design spectrum of an engineering site can be determined directly by the Code of Seismic Design of Buildings,while the bedrock design spectrum usually has to be obtained through specific seismic safety analysis,which is usually affected by the potential earthquake source division,earthquake activity parameters,bedrock motion attenuation relation,etc.; and the seismic safety analysis cannot condiser the associated soil condition,so the bedrock design spectrum is often inapprociate with the surface design spectrum. To overcome this problem,a method for inversion of bedrock design spectrum of engineering sites is proposed. Based on the theory of one-dimensional wave propagation in layered half-space,the design spectrum at ground surface is inversed to design spectrum at the bedrock,considering soil nonlinearity by the equivalent linearization method. The equivalent shear strain is obtained from the average shear strain of all acceleration time history samples. One of the advantages is that the bedrock design spectrum obtained by this method is appropriate with the soil nonlinearity of the engineering site. The method has some value in engineering practice.更多还原