The shallow buried bucket foundation is a new type of offshore wind turbine foundation. It has smaller differential settlement and is easier to install than the traditional foundation. But engineering design method for shallow buried bucket foundation isn't mature at present. It's usually considering cyclic loading as static loading to design. That can't reflect bearing characteristics of bucket foundation under cyclic loading. In the paper, the bearing characteristics of bucket foundation under cooperative action of static loading and cyclic loading is researched by model test according to engineering project data. The influence of cyclic loading amplitude on bearing capacity is analyzed through test data. The regularity of bucket rotation center depth is obtained by displacement data which provides reference for engineering design.
China has abundant wind power resource. Among all types of wind power resource, offshore wind resource is the focus of Chinese wind energy development for the advantages of short distance to electricity area, high wind speed, small turbulence intensity and steady direction. According to the relevant provisions of the new energy law of the People's Republic of China in 2006, the total installed capacity of China's wind turbines will exceed 3000 MW by 2020. Although the prospect of offshore wind energy is promising, the construction of offshore wind farm faces many technical difficulties. One urgent difficulty to solve is the normal operation of wind turbines under the great bending moment. The shallow buried bucket foundation was proposed by Tianjin University to solve the difficulty. The length-diameter ratio of shallow buried bucket foundation is unusually less than 0.5, and the bucket diameter can be 40 m. Compared to the conventional foundation, shallow buried bucket foundation has advantages of easy installation (Det Norske Veritas 1992; Xu 2005; Senders 2009; Liu 2016) and effective control of differential settlement. At present, three prototype wind turbines using the shallow buried bucket foundations have been put into use. The wave loading of the offshore wind turbine can't be neglected for the great value of the wave loading. Because of the short application time, the design of shallow buried bucket foundation is conservative for its unclear bearing capacity with the wave action. So how to estimate the cyclic loading action on bearing capacity of the bucket foundation is one of the most important subject of the shallow buried bucket foundation.
