非线性场地基岩功率谱反演的一个方法

A method for inversion of power spectrum of bedrock considering soil nonlinearity

提出了非线性场地基岩功率谱反演的一个方法。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,通过给定的地表运动功率谱反演得到基岩运动功率谱,进而利用基岩运动功率谱模拟基岩随机地震动。土层等效剪应变取各样本等效剪应变的平均值。并利用金井清功率谱和日本Kik-Net台站记录对该方法进行了验证。结果表明,该方法能够较为方便且准确的得到符合场地非线性特性的基岩功率谱,具有一定的工程应用价值。

A method for inversion of power spectrum of bedrock considering soil nonlinearity of the site is proposed.Based on the one-dimensional layered site wave theory,the equivalent linearization method is used to consider the nonlinearity of site soil.The power spectrum of bedrock motion is obtained by inversion of the given power spectrum of surface motion,and then the random ground motion of bedrock is simulated by the power spectrum of bedrock motion.The equivalent shear strain of soil layer is taken as the average of the equivalent shear strain of each sample.The method is validated by using Kanai-Tajimi power spectrum and Kik-Net station records in Japan.The results show that this method can obtain the power spectrum of bedrock which accords with the soil nonlinearity of the site conveniently and accurately.The method has certain engineering application value.