Interaction model for horizontal dynamic response of monopile-friction wheel composite foundation in marine area

Abstract

To ensure the expansion of offshore wind power market under economical investment, the monopile-friction wheel composite foundation is proposed by previous scholars. This paper develops a theoretical model to obtain the horizontal dynamic response of the composite foundation in marine environment. The soil reaction excited by the pile’s vibration is calculated based on the Novak’s thin layer model and Biot’s wave theory, and the shear force caused by the friction wheel can be obtained by use of the three-dimensional continuum mechanics theory. The dynamic equations of pile shaft and hydrodynamic pressure are described by Euler-Bernoulli beam theory and radiation wave theory, respectively. The correctness and accuracy of the analytical framework have been confirmed by comparing the similar results of existing literatures. Finally, the influences of the diameter and thickness of the friction wheel on the horizontal dynamic characteristics and displacement filed of seabed surface have been thoroughly discussed. The main findings can be drawn that the horizontal vibration characteristics along the composite foundation decrease with increasing the diameter and thickness of friction wheel, and thus the advantages of the monopile-friction wheel composite foundation compared to single pile is proved with great potential of progress.