Soil Liquefaction Effects on the Seismic Response of Monopile Foundation for 10-MW Offshore Wind Turbine in Taiwan

This paper is to study the influence of soil liquefaction on the seismic response of a monopile foundation for the Technical University of Denmark (DTU) 10-MW reference wind turbine (RWT) on the west coast of Taiwan. Taiwan is located in seismically active regions, and the soil conditions of Taiwan's offshore wind farms are softer than those in Europe. Therefore, there is significant interest in assessing the behavior of a wind turbine subjected to seismic load. Based on the flexible volume method and the practical, two-surface plastic constitutive model for sand (P2PSand), the two foundation models of the DTU 10-MW RWT are employed to carry out a series of seismic design load cases as defined in DNV-RP-0585. The results show that soil liquefaction has significant influence on the dynamic response of the DTU 10-MW RWT with monopile foundation under the local environmental conditions in Taiwan. In particular, vertical displacements and rotations are significantly amplified by soil liquefaction during strong ground motions. It means that without considering the potential effect of soil liquefaction, structural responses, including displacement and rotation angle, may be greatly underestimated.