| General Secretary Xi Jinping once pointed out the maritime power strategy is an important strategy that China needs to adhere to for a long time,including the protection,development and utilization of the oceans,as well as the control of the oceans.Because the development of Marine resources is more and more into the deep sea,and the deep sea mostly uses the mooring structure,so the study of the stability of the deep sea mooring structure becomes more and more important.Suction anchor foundation has been widely used in Marine mooring structures because of its excellent bearing capacity,environmental friendliness and economy.Because the height of bucket foundation is smaller than other types of foundation(such as pile foundation),the bearing capacity of bucket foundation mainly comes from shallow soil.The shallow soil in China’s sea area is mostly soft clay,and soft clay is more vulnerable to the weakening effect caused by dynamic load.Therefore,this paper uses the secondary development function of finite element analysis software ABAQUS to write a subroutine to study the bearing capacity of bucket foundation under the influence of cyclic weakening.The main research results of this paper are as follows:(1)The finite element model of barrel foundation is built,and the boundary conditions,contact Settings and mesh division in the finite element model are explained.The accuracy of the finite element model established in this paper is verified by comparing the finite element model with the upper and lower limit solutions and research results of previous studies.(2)The corresponding user-defined subroutine was developed with Fortran language,and the cyclic weakening law was realized in the finite element software Abaqus.By comparing the numerical simulation results of the cyclic weakening finite element model with the experimental results,the accuracy of the cyclic weakening model established in this paper is verified.(3)The bearing capacity of Bucket Foundation under combined load V-H is obtained by finite element calculation,the failure mechanism of bucket foundation under combined load is analyzed,and the normalized failure envelope is drawn,the failure envelope equation considering the ratio of length to diameter of bucket foundation and the Coefficient of inhomogeneity of soil mass under combined load is given.It provides a reference for the later research on the bearing capacity of Bucket Foundation when the cyclic weakening effect of clay is considered.(4)The bearing capacity of the bucket foundation of the Marine mooring structure considering the cyclic weakening effect of soft clay is obtained through finite element calculation,and the failure envelope surface is drawn;The effects of cyclic load vibration,amplitude and length-diameter ratio of bucket foundation model on the failure envelope of the bearing capacity of bucket foundation are analyzed.The damage mechanism of bucket foundation under the influence of cyclic weakening effect is analyzed for different loading angles and length-diameter ratio models.The equation for calculating the failure envelope surface of the barrel foundation is given when the soft clay is considered.Then a layered soil model is established according to the engineering practice to consider the influence of cyclic softening of soil under cyclic load on the bearing capacity of bucket foundation in inhomogeneous clay. |
