Torsional dynamic response of pipe piles based on additional mass model

The torsional dynamic response of pipe piles is investigated based on the additional mass model. It can provide a new theoretical basis for non-destructive integrity testing of pipe piles, design of dynamic foundation and earthquake-resistant design. First, the analytical solutions for complex stiffness and velocity response in the frequency domain and the corresponding quasi-analytical solutions for velocity response in the time domain at pile head are derived. Then, the rationality and accuracy of the solutions are verified by comparing the dynamic behaviors of the pipe piles calculated by the additional mass model with those based on the plane strain model. Finally, the influences of the soil plug height and the damping effect between soil plugs and pipe piles on the torsional dynamic response of pipe piles are analyzed. The results show that the soil plug height and the damping effect between soil plugs and pipe piles have an important influence on the torsional complex stiffness of pipe piles. The test torsional velocity of pipe pile decreases as the soil plug height and the damping effect between soil plugs and pipe piles increase.