Influences of bulkheads on bearing characteristics of composite bucket foundation of offshore wind turbines

In order to enhance the strength of the structures and the stability of the floating process and to realize the fine leveling of the sinking process, the bulkheads must be installed in the composite bucket foundation. However, the researches on the influences of bulkheads on the bearing characteristics of foundation are not in-depth. Taking the composite bucket foundation of 6.45 MW offshore wind turbine as an example, a series of FEM numerical simulations are conducted to study the influences of honeycomb bulkheads as well as bulkheads form, height and thickness on the bearing characteristics under different rotational states and structural dimensions. The results show that the bulkheads can obviously enhance the bearing capacity, and the enhancement effect increases with the increase of rotational angle. When the aspect ratio of bucket foundation is 0.33, the bulkheads have the best enhancement effect for bearing capacity. When the rotational angle reaches 0.5° which is the maximum rotational angle of offshore wind turbine in normal operation, the bearing capacity of the foundation can be increased by 9.23%. The bulkheads can not change the motion law of the rotation center, but the influences of bulkheads on the vertical position of rotation center are obviously greater than those on the horizontal position. The influences of bulkheads on the bearing capacity of composite bucket foundation should be considered in the design. In addition, the form, height and thickness of bulkheads can be optimized appropriately.