Horizontal dynamic response of offshore large-diameter pipe piles

Abstract

The dynamic response of an offshore large-diameter pipe pile-soil-water system under horizontal dynamic loads is analytically studied in this paper. The hydrodynamic pressure of the outer and inner seawater are obtained by the inviscid compressible fluid theory, and the lateral resistances of the outer and inner soil are obtained based on the viscoelastic dynamic continuum models. The pile response is obtained by utilizing the continuity conditions at the soil-pile and seawater-pile interfaces along the pile shaft. Results of the proposed solution are validated against FEM numerical results and against existing analytical and experimental results. The effects of hydrodynamic pressure from seawater on the pile head displacement and on the natural frequency are subsequently investigated for different problem parameters. Finally, the sensitivity of horizontal dynamic responses of the pipe pile-soil-water system in the frequency range to certain key parameters, such as water depth, pile length above the seawater, thickness of the soil, outer and inner radius of the pipe pile is analyzed.