Influence of soil plug effect on the vertical dynamic response of large diameter pipe piles

Abstract

The influence of soil plug effect on the dynamic response of large diameter pipe piles during low-strain integrity testing is investigated based on the additional mass model, considering the soil plug weight and displacement phase difference between soil plug and pipe pile. An analytical solution that can consider the stress wave propagating both in the vertical and circumferential directions is derived in the frequency domain through the transfer function method. The corresponding quasi-analytical solution in the time domain for the pipe pile subjected to a vertical semi-sinusoidal impact force is then obtained by utilizing the Fourier transform technique. The validity and accuracy of the solution presented in this paper is compared against a series of model tests and field experiments of pipe pile. Utilizing the developed solution, a parametric study is performed to illustrate the influence of soil plug properties, pipe pile properties and the impulse width of impact force on the composite velocity of the longitudinal stress wave propagating in pipe pile, and the applicability of the plane-section assumption adopting in pipe pile.