عنوان مقاله [English]
Offshore wind turbines are light and sensitive structures. There are several types of foundations for offshore wind turbines. One new foundation concept in relation to offshore wind turbines is bucket foundations. In this study, results of three-dimensional finite element analyses under pure vertical, horizontal and moment loading as well as combined load in medium dense sand are presented. Numerical analyses are carried out using the Mohr Coulomb material model and the three dimensional finite element software Plaxis. Parametric analyses are performed at different length-to-diameter embedment ratios and failure mechanisms of bucket foundations are compared for pure and combined loading. The load- deformation curves of bucket foundations under general loading are investigated analytically. The failure mechanism of the bucket foundation under pure vertical loading is known to be dependent of the pure settlement and no horizontal displacement and rotation. For pure horizontal loading and moment, occurred coupling between the horizontal and rotational degrees of freedom in foundation system with larger sliding for pure horizontal load and larger rotation for pure moment. Failure mechanisms under combined loading depending on horizontal load eccentricity rate and applied moment induce variable horizontal displacement and rotation in foundation.