Load-bearing Behavior of Offshore Rock Socketed Monopile Foundation Regarding Different Rock Mass Classification

With the increasing electricity demand in China, wind power has been heavily developed in recent years. It is important to stabilize the wind turbine foundations in rock bedded near the sea area while installation. Based on different rock classification standards (GB 50218 and GSI), this paper numerically analyzed the load capacity of rock socketed monopile. When the rock class is high (class III and above), under effective socketed depth, the rock-socket effect is important, and the pile tip deflection is nearly 0, which could be considered as a clamping constraint. In this case, even if the rock quality around the pile tip decreases a little or becomes a little weakened, the pile deformation and internal force will not change a lot. However, when the rock mass class is lower than IV, the pile tip load capacity will largely decrease. The definition of rock mass parameters is also important when analyzing rock socketed monopile. In conclusion, it is suggested to take GB 50218 as a reference. BQ engineering rock mass classification and its corresponding rock mass parameters could be applied. Also, the M-C model is suggested to be used for some related work.