Lumped-parameter model of pile group impedance function

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.