摘要
本文首先引入一个“二维”时间座标，并通过出因子δ－θ推广的动力显式差分方程，使得在任何情况下上层非线性地震反应均可获得稳定、收敛的计算结果。为了进一步底探讨基底及其界面的扰动影响，文中给出了三种不同的差分格式，结果虽基本一致，但仍以中心差分格式为宜。土的非线性本构关系，在多种可供采用的模型中，本文选取了工程上常用的“双曲骨架”模型，其优点在于：在积分过程中，只需调整两个相关因子，即可同时拟合土层的实测阻尼。最后，本文通过几个典型算例的分析表明，对于土层结构复杂且间有软弱（低速）层时，其地震反应与等效线性方法给出的相应结果相比，具有明显差异。
First of all,this paper introduces a'two -dimensional'time axis and the dynamic explicit difference equation is extended through the factors of both δ and θ such that it is sure to obtain the stable and reasonable results for computing nonlinear seismic response of one-dimensional soil layers whatever conditions of the deposits are. Three difference methods are presented in time domain in order to compare with the effects of bedrock and its interface motions,and the responses indicate that the centre difference method is appropriate although they are essentially equivalent.The current hyperbolic function in engineering is adopted in existing nonlinear constitutive models of soil since only two correlative parameters must be adjusted to fit the measured damping ratios in numerical integrating of the difference equation. Finally,a few typical examples are given. Numerical analysis shows that compared with the linearization method,the seismic responses are obviously different under conditions of complex deposit and filling it with soft(lower velocity)layers.
出处
《地震工程与工程振动》
CSCD
北大核心
1996年第4期1-14,共14页
Earthquake Engineering and Engineering Dynamics
基金
国家地震局"八五"规划课题
关键词
土层
地震反应分析
地震波
阻尼拟合
δ-θ法
seismic response anlaysis,nonlinear constitutive relation,damping fitting,two-dimensional time axis
