Soil-Pile Dynamic Interaction in the Viscous Damping Layered Soils

Abstract

Modeling surrounding soil as a three-dimensional axisymmetric continuum and considering its wave effect, soil-pile dynamic longitudinal interaction in viscous layered soils is studied. The pile is assumed to be vertical, elastic and of uniform section, and the soil is layered and visco-elastic. Longitudinal vibration of pile in viscous damping layered soils undergoing arbitrary load is theoretically investigated. By taking the Laplace transform, the question can be solved in frequency domain. Utilizing two potentials combined with impedance transfer functions, analytical solutions for both the impedance function and mobility at the pile head in frequency domain are yielded. With the convolution theorem and inverse Fourier transform, a semi-analytical solution of velocity response in time-domain undergoing a half-cycle sine pulse force is derived. Based on the solutions proposed herein, the effects of variety of soil modulus on mobility curves and reflection wave curves are emphatically discussed. The results shows that there is a smaller peak between every two adjacent larger peaks on the mobility curve in layered soil, and larger peak cycle reflects the location where the modulus of the soil varies abruptly. The conclusions can provide theoretical guidance for non-destruction test of piles.