Dynamic Response And Influencing Factors Analysis Of Large Diameter Single Pile Foundation Of Offshore Wind Power

Wind energy is a green and renewable energy developed vigorously by all countries in the world in the 21st century.China is rich in offshore wind power resources,and offshore wind power industry is developing rapidly.As the most widely used fan foundation form,super-large diameter single pile foundation has great development potential and space.Super-large diameter single pile foundation is subjected to wind,wave and other dynamic loads during its service period.Under such circumstances,transient dynamic analysis of the pile foundation will be of great significance in determining the loading behavior of the pile foundation,checking the stability of the pile foundation and guiding the optimization of actual construction.Based on the water level and geological conditions of an offshore area in Rudong County,the finite element simulation software ABAQUS was used to carry out numerical simulation,The dynamic response characteristics of offshore wind power large diameter single pile foundation under wave loads and combined loads were studied.and the influence of different factors on the dynamic response of large diameter single pile foundation in the numerical model was analyzed.The influencing factors include load size,load location,compressive modulus of soil and degree of freedom of pile.The dynamic characteristics of offshore wind power large diameter single pile foundation were obtained by different magnitudes of influencing factors,which can provide valuable reference for practical construction.The following conclusions are drawn:(1)Taking the sea area of Rudong County as the background,the structure of offshore wind power single pile foundation is appropriately simplified,and the pile-soil finite element model is selected.The finite element model of offshore wind power single pile foundation is established by ABAQUS finite element numerical simulation software.The modal analysis of the single pile foundation is carried out,and the first 12 modal shapes of the structure are obtained.According to the comparison,it is found that the modal shapes of single pile foundation are within the frequency range,and the natural frequencies are similar,with little difference in numerical values.(2)The transient dynamic analysis of offshore wind power single pile foundation under wind wave load is carried out,and the extreme values of displacement,stress,velocity and acceleration of key parts and their corresponding dynamic response time history curves are obtained.The main characteristics are as follows:First,the maximum value of structural displacement always appears at the pile top of the single pile foundation;Second,the place where the structural stress value is the largest is mainly at the position where the pile body is buried to 15m.(3)In the pseudo-static algorithm,the wave load of Periodicity is staticized,and the displacement and stress nephogram and extreme value of offshore wind power pile foundation under the pseudo-static load are obtained.(4)The displacement and stress of offshore wind power single pile foundation are compared and analyzed by changing the load size,the position of load action point and the compression modulus of soil.The following main conclusions are obtained.First,the displacement,stress,velocity and acceleration of offshore wind power single pile foundation will increase with the increase of wave load.Secondly,the position of wave load action point has the greatest influence on the stress of offshore wind power pile foundation,followed by displacement,velocity and acceleration with little influence.Third,with the increase of the compressive modulus of the foundation soil,the displacement of the key parts of the single pile foundation gradually decreases,with the pile top showing the most obvious,the stress of the key parts of the single pile foundation gradually increases,with the most prominent performance at the depth of 15m.