群桩基础阻抗函数的集总参数模型研究

Lumped-parameter model of pile group impedance function

利用改进后的Chebyshev多项分式进行复数拟合,得到群桩基础阻抗函数可扩展精度的集总参数模型,以获取时域分析和非线性分析的群桩基础参数。基于薄层法求解得到半无限地基中群桩基础的阻抗函数,利用改进的Chebyshev多项式的比值表示地基的动力柔度函数,将改进的Chebyshev多项分式表示成部分分式的形式,最后将其等效为两种基本类型的集总参数模型。通过与薄层法求解得到的地基动力刚度阻抗函数进行比较,给出的集总参数模型能在很宽的频段上与弹性半空间解吻合良好,得到的集总参数可以直接运用到群桩地基-结构相互作用的时域分析和非线性分析中。

The pile group impedance function was considered based on thin layer method,and attention was paid on the application of Chebyshev complex polynomials in the development of extensible lumped-parameter model of pile group foundation.The present method is an important extension to the concept of polynomial-fraction approximation in the foundation modeling.In the analysis,the normalized flexibility function was adopted to improve the accuracy of the model and to reduce the number of parameters in modeling.The accuracy and validity of the lumped-parameter model was extensively investigated in the case of pile group foundation.The proposed method may be easily applied to analyze various practical problems in soil-structure interaction in both frequency domain and time domain.