Research On Bearing Characteristics Of Suction Bucket Foundation In Sand Under Cyclic Loading

With the rapid development of Marine energy industry,bucket foundation has been paid attention to by various offshore platform projects for its advantages of low engineering cost,good bearing capacity and suitable for Marine environment,etc.,and has been widely used in offshore projects at home and abroad.But the Marine environment is extremely complex,in addition to the bucket foundation by its upper offshore platform structure and large dead weight contribute to long-term effects of vertical static load,but also by wind,waves,currents,such as long-term cyclic loading for use,will cause the bucket foundation bearing capacity is insufficient,and the accumulated deformation of foundation,easy to make Marine buildings have collapsed,buckling failure.This puts forward higher requirements for its carrying capacity and stability.Therefore,based on the laboratory model test and finite element numerical analysis software ABAQUS,this paper conducts an in-depth study on the bearing characteristics of suction bucket foundation in sand under cyclic load.The main research contents are as follows:(1)Using indoor bucket foundation model test analysis,according to the displacement control method,apply unidirectional horizontal cyclic displacement and vertical cyclic displacement at the center point of the top of the bucket foundation,and study the effect of buried depth and cyclic amplitude on the bucket foundation in different orders.Bearing characteristics under cyclic loading.The experimental results show that under the action of cyclic loading,the greater the buried depth,the better the bearing capacity of the bucket foundation;with the increase of the number of loadings,the earlier the bucket foundation with the larger the cyclic amplitude is damaged and the lower the bearing capacity.(2)Based on the finite element numerical analysis software ABAQUS,a three-dimensional numerical calculation model of the bucket foundation was established to study the effect of the buried depth and the amplitude of the cyclic load on the bearing characteristics of the bucket foundation under the separate effects of horizontal cyclic load,vertical cyclic load,and rotating cyclic load influences Numerical calculation results show that under the action of cyclic load,the cyclic secant stiffness of the bucket foundation increases with the increase of buried depth,and the cyclic secant stiffness decreases with the increase of cyclic load amplitude;horizontal and vertical Under a single cyclic load,when the amplitude is small,the stiffness of the bucket foundation gradually increases with the number of cyclic loading;when the amplitude is large,the cyclic secant stiffness of the bucket foundation gradually decreases with the increase of the number of cyclic loading;cyclic load The larger the amplitude,the more obvious the impact of loading times on the load-bearing characteristics of the bucket foundation.Under the action of the rotating cyclic load,the cyclic secant stiffness of the bucket foundation tends to decrease slightly with the increase of the number of cyclic loads at different cyclic amplitudes;the greater the cyclic load amplitude,the greater the cyclic secant stiffness of the bucket foundation small.