Vertical dynamic response of soil surrounding pile-pipe pile-soil plug by considering lateral inertial effect

Compared with the solid pile, the vertical vibration of open-ended pipe pile is much more complex due to the complicated dynamic interaction between the soil plug and the inner wall of pipe pile. Therefore, the dynamic interaction of pipe pile and soil should be further investigated by considering the effect of soil plug. Firstly, by considering the lateral inertial effect and viscous property of pipe pile, governing equations of vibration for the pile surrounding soil-pipe pile-soil plug system under vertical dynamic loading are established based on the Rayleigh-Love rod model and additional mass model. Then, the analytical solution of velocity response in frequency domain at the pipe pile top is obtained by means of the integral transform technique and impedance function transfer method. The velocity response in time domain is also derived with half-cycle sine pulse applied on the top of pipe pile. Finally, the rationality of the theoretical solution derived in this paper is verified by comparing with the existing solutions and experimental results. Meanwhile, discussion about the influence of the design parameters of pipe pile on the vertical dynamic response at the pile top indicates that the dispersion effect of stress wave propagating in the pipe pile signifies with the increase of pipe pile section and the decrease of pipe pile length when the other parameters of soil-pipe pile system is constant. For the piles with same outer diameter, the reflective signals at the upper surface of soil plug and the pile tip are easier to be detected as the width of pile shaft increases, leading to the more reasonable assessment of the pipe pile integrity. © 2017, Science Press. All right reserved.