Numerical Modelling of Lateral-Moment Bearing Capacity of Friction Wheel Foundation for Offshore Wind Turbine

Offshore wind turbines are generally subjected to large lateral-moment loadings induced by wave, wind, and ice. Friction wheel foundation, which is a mono-pile with a friction wheel near the seabed, has been proposed and proved by previous studies to effectively increase the stiffness and bearing capacity of the mono-pile under later-moment loading. In this paper, a new design of friction wheel filled with gravel was studied by numerical modeling. Numerical models of friction wheel foundations were established, as well as the mono-pile foundations. The load-displacement curves are validated by centrifuge tests. The stress and strain distributions along the mono-pile and friction wheel are depicted to discuss the mechanism of load transfer and the resistance contribution that the wheel makes. To optimize the design, several numerical models were built to carry out a parametric study regarding the annulus size between the outer ring and the inner ring and the height of the gravel wheel. The results can be applied to future design of the friction wheel foundations and predict the performance of this hybrid foundation under lateral-moment loading condition in offshore wind engineering.