The Bearing Characteristics Of Suction Bucket Foundation In Saturated Soft Clay Under Wind And Wave Cyclic Loads

With the continuous development of the economy,there are numerous challenges,such as the depletion of traditional energy sources like coal,natural gas,and oil,along with environmental pollution.Wind energy,as a clean and green energy source,has garnered widespread attention and holds tremendous potential for growth.China’s wind power industry,particularly offshore wind power,has seen significant growth in recent years.During its service life,offshore wind turbines are subjected to complex environmental loads,including the horizontal cyclic action of wind and waves,which can cause repeated shear forces and overturning moments at the base of the foundation.If the foundation corner becomes too large,it will not only impact the wind turbine’s normal operation,but also pose great potential safety risk to the safety of the overall system.Therefore,it is of great significance to study the bearing characteristics of offshore wind foundation under environmental cyclic loads for the security of offshore wind turbines.This thesis focuses on the suction bucket foundation in saturated soft clay and analyzes its bearing characteristics under cyclic wind and wave loads.The primary research topics include:(1)The indoor cyclic dynamic triaxial test of saturated soft clay was carried out.Based on the test data,the strength decay equation of saturated soft clay under cyclic loading was fitted.Through secondary development in the finite element software ABAQUS,the strength decay equation of soil was further implemented so as to establish the soil strength decay model.(2)The theory of wind load calculation is summarized.The harmonic superposition method and fast Fourier transform are used to simulate the pulsating wind speed according to Davenport spectrum,so as to calculate the instantaneous wind speed and instantaneous wind load acting on each point of the tower.(3)The theory of wave load calculation is summarized.The micro-amplitude wave theory in wave motion and P-M spectral are used to simulate the random waves.Then calculate the random wave load acting on the tower by Morison formula.(4)Numerical simulations were performed using the finite element analysis software ABAQUS.A three-dimensional finite element model of bucket-soil interaction in a saturated soft clay was established using a second developed soil strength decay subroutine.And the calculated wind and wave loads were applied to the finite element model to analyze the bearing characteristics of suction bucket foundation in saturated soft clay under different working conditions.