A framework for evaluating the bearing capacity of offshore wind power foundation under complex loadings

Offshore wind power foundations are known to bear complex loadings, not only vertical loading V induced by self-weight, but also horizontal loadings H induced by wind, wave and current, and the bending loading M transferred from superstructure. In this paper a framework for evaluating the bearing capacity of the foundations is presened and the bearing characteristics of offshore wind power foundation under combined horizontal, vertical and bending loadings are analyzed. The bearing capacity of offshore wind power foundation under unidirectional horizontal, vertical and bending loadings is examined, and the relationship between the ultimate bearing capacity and the ratio of diameter to length of pile foundation is obtained. Based on the side-swipe method, the envelope of bearing capacity and failure mode of offshore wind power foundation in V-H, V-M, H-M loading space and V-H-M loading space are studied in details, and the parameter analysis of the envelope of foundation bearing capacity in different loading space are discussed. Finally, a simple and practical method is proposed to judge the stability of the offshore wind power and the seabed. A verification example reveals that the estimates of the presented framework shows good agreement with observations.