变参数土层的动力特性和地震反应分析

应用模态摄动原理和一维剪切波动方程，建立了变参数土层自振特性的简捷计算方法。，从而为计算各类变参数地震反应提供了一个有效的计算手段。这一方法不仅适用于分层均匀土层，也适用于土介质物理特性沿深度不均匀变化的土层。这种变化规律既可用解析函数表示，也可采用列表函数

Dynamic Analysis for Modal Characteristics and Seismic Responses of Soil Layer with Variable Properties

A simplified method is suggested for determining the modes of the soillayer with varible properties- Therefore an effective computing approach isdeveloped for analyzing the seismic responses of different types of soil layers. Thismethod is based on the one-dimensional shear wave equation and the modalperturbation technique. The modal characteristics of the complicated soil layer arecalculated approximately in a subspace spanned by several lower modes of anequivalent homogeneous soil layer with the same depth, average shear modulusand mass density. As a result, solving the wavo equation with variable coefficientsis replaced by solving the linear algehraic equations. The simplified method can beapplied easily to the layored homogeneous soil, and also to the soil layer in whichthe property of soil media changes with depth in any form, such as analytical ordiscrete form. The numercial results show that precision of the method is betterthan the othor methods suggosted before.