2020 Volume 76 Issue 2 Pages I_132-I_137
The monopile gravity-type foundation, which is the foundation type of offshore wind power generation facilities, was examined when the shape of the RC bottom slab was circular or octagonal, which is lighter than rectangular and lower cost. In order to obtain information on the stability and the uplift pressure acting on the bottom slab under the eccentric inclined load due to wind and waves, a cross-sectional hydraulic model test of a 5 MW wind turbine and a numerical analysis with a numerical wave tank CADMAS-SURF / 3D were performed.
As a result, it was stable up to 7-11 % above the overturning limit on the design, and the bearing capacity of the rubble foundation was not destroyed at the time of the overturning, so that the conventional stability and bearing capacity checking method can be applied mutatis mutandis. Furthermore, regardless of the plane shape of the bottom slab and the wave conditions, the uplift pressure distribution is almost uniform in the direction orthogonal to the wave direction, and the contribution rate of the vertical wave force moment during the design wave action is about 8 to 14 % at the maximum.
