Comparative Study On Liquefaction Resistance Of Sand Foundation Of Mono-bucket Foundation And Composite Bucket Foundation For Offshore Wind Turbines

With the rapid development of the global economy,the demand of sustainable and renewable energy is increasingly enormous.Lots of countries have set their sights on offshore wind resources.Many countries have established huge offshore wind farms with diverse foundation structures applied to support wind turbines.The bucket foundation occupies a certain market due to its advantages of simple structure,convenient installation and easy recycling,simultaneously it has broad development prospects.At present,many studies have been carried out on the bucket foundation,but there is still a lack of research on its seismic performance.Since China is a country with frequent earthquakes,it is necessary to study the seismic performance of the bucket foundation.Due to the high rigidity of the foundation structure,the probability of structural damage under earthquakes loading condition is small.The important reason for foundation failure is the excessive displacement of the foundation structure due to liquefaction or uneven settlement of the soil,which will lead to the loss of foundation bearing capacity.Therefore,the research object of this paper is the soil near the bucket foundation.This paper conducts a comparative study on the response of the soil near monobucket foundation and composite bucket foundation under earthquake loading condition.The research content includes the following aspects:(1)By carrying out a large-scale shaking table test,the excess pore water pressure,excess pore pressure ratio and acceleration of the foundation soil under earthquake loading condition are analyzed,and the effect of the foundation on the soil under earthquake loading condition is clarified;(2)According to the test results,the soil responses of the mono-bucket foundation and the composite bucket foundation under earthquake loading condition are compared,and the effect of the internal sub-structures in the composite bucket foundation on the seismic performance of the foundation soil is clearly elaborated.(3)Using the finite element software ADINA for numerical simulation,considering that the research object is saturated soil,select the porous media material in ADINA to establish the soil model,obtain the excess pore pressure data and judge the liquefaction of the soil based on the effective stress method.Simultaneously extract the acceleration data of the foundation soil under earthquake loading condition,and use the numerical simulation results to compare the response of the soil near the monobucket foundation and the composite bucket foundation.(4)Finally,the test results are compared with the numerical simulation results to verify the reliability of the finite element simulation,making the conclusion more reliable and persuasive.