In order to obtain the dynamic response of defective large-diameter pipe pile in low strain integrity testing when subjected to transient concentrated load, a computational model and wave equation of large diameter pipe pile with variable wave impedance were established based on radial invariability assumption. The analytical solution of wave equation in frequency domain was obtained by Laplace transformation method. The dynamic responses in time domain were obtained by Fourier inverse transformation. The results of analytical solution were compared with that of 3D finite element method and 1D wave theory. The results indicated that the results of analytical solution well matched the 3D-FEM results. The velocity responses at 90°point calculated by 3D-FEM, analytical solution and 1D wave theory had little difference. The dynamic responses at different points on top of the pile showed that the arrival time of incident wave crests varied with radius angle. The smaller the radius angle, the earlier the arrival time. The arrival time of defect reflected wave crests was different among different points when depth of defect was not very deep. However, the difference was decreased when the defect was deeper. The high-frequency interference was the least at 90°point. The results of the analytical solution could well meet the measured results.
