Seismic Analysis of Monopile Supported Offshore Wind Turbine

摘要

Seismic analysis of monopile supported offshore wind turbine is studied, with the Lely offshore wind farm as an example. Based on the unified plasticity model for large post-liquefaction shear deformation of sand, a three-dimensional dynamic finite element analysis is established. Then following results are got. Under the load coupling of wind and earthquake, the pile occurs large displacement and inclination which exceeds the operation safety line 0.17°. The increase of bending moment is small, which indicates that the pile has weak anti-overturning capability and relies mainly on the soil reaction force around. Therefore, the pile rotates in center of the pile bottom under load, showing the increase in displacement. And the seabed sand liquefaction increases the pile inclination. Both the inertial interaction of the structure and foundation and the pile-soil interaction are large, which increases the deformation and results in residual bending moment of the pile. Therefore, seismic analysis and safety assessment of pile foundation must be studied for offshore wind farms in earthquake areas.