New method to calculate apparent phase velocity of open-ended pipe pile

The apparent phase velocity of open-ended pipe piles after installation is difficult to predict owing to the soil-plug effect. This paper derives an analytical solution to calculate the apparent phase velocity of a pipe pile segment with soil-plug filling inside (APVPSP) based on the additional mass model. The rationality and accuracy of the developed solution are confirmed through comparison with the solution derived using the soil-plug Winkler model and experimental results. A parameter combination of the additional mass model that can be applied to concrete pipe piles used most commonly is recommended. The attenuation mechanism of the soil plug on the APVPSP is clarified. The findings from this study demonstrate that the APVPSP decreases with the mass per unit length of the pile, but has nothing to do with the material longitudinal wave velocity of the pipe pile. The APVPSP decreases significantly as the impulse width increases; however, for pipe piles without soil-plug filling inside, the impulse width has negligible influence on the apparent phase velocity.