Energy dissipation by external damping in marine vibratory pile sinking

Abstract

Various forms of energy dissipation by external damping are generated when the high-frequency vibrating pipe pile penetrates into the subsea strata. The lack of clarity in the damping mechanism limits the efficiency of marine vibratory pilesinking. In this study, a longitudinal vibration model of a pipe pile considering the coupling between the pile and the subsea strata is established. The attenuation coefficient for pile side viscous damping, the radial radiated power considering the Poisson effect of the pipe pile, and the work by the damping force at the pile bottom are derived. Adopting numerical simulations, the vibration characteristics of the pile and the energy dissipation mechanism of external damping in marine pilesinking are presented. The results show that the energy dissipated by external damping increases with the input frequency. The radial radiation loss is more than the damping energy on the pile side at the same frequency. Wall thickness affects the dissipation of viscous damping energy and radially radiated energy. Through the modulation of the input frequency and the optimization of the pipe pile structure, the energy dissipated by external damping can be reduced and the efficiency of pile sinking can be improved.