Abstract:

To mitigate the long-term impact of horizontal loads (such as wind, waves and currents) on offshore wind turbines, a finite element model for the ultimate bearing capacity of heterogeneous clay single-pile foundations was developed using ABAQUS software. Temperature was employed as a virtual variable to reflect the relationship between shear strength of heterogeneous soil and depth. The Model Change technique was employed to achieve geostatic equilibrium, and the obtained results regarding the variation in horizontal loads on single-pile foundations were compared with centrifuge test outcomes to validate accuracy. Combining the failure modes of soil under horizontal ultimate loads for both rigid and rigid-flexible piles, the influence of parameters such as aspect ratio, soil elastic modulus coefficient and pile-soil friction coefficient on the horizontal ultimate bearing capacity of single pile foundations was analyzed. The findings indicate that with an increase in pile embedment depth, the pile transitions from a rigid state to a rigid-flexible state, and the soil failure mode shifts from wedge and rotational failure to wedge, full-flow and rotational failure. The soil elastic modulus coefficient has a minor impact on the horizontal ultimate bearing capacity of single-pile foundations, while the aspect ratio and pile-soil friction coefficient exert a significant influence.

Key words: heterogeneous clay, single pile foundation, horizontal ultimate bearing capacity, offshore wind turbines, finite element model