A Method Of Predicting Embedded Trajectory Based On The Finite Element Calculation Of Bearing Capacity Of Drag Anchor

With the development of marine resources,the design of mooring system becomes more and more important.Drag anchor is an important part of mooring system,and the mooring line is fixed in the seabed by anchor,which is one of the common anchorage foundation forms.It is very important to estimate the embedded trajectory of drag anchor during the installation process,which is of great significance to the safety design of mooring system.At present,the method of drag anchor embedded trajectory prediction based on incremental calculation proposed by Neubecker and Randolph(NR)is relatively recognized.In this paper,the method is improved as follows:Firstly,introduces the research methods and progress of the drag anchor embedded trajectory prediction and the theoretical base,including incremental calculation,the catenary equation is derived,the bearing capacity of drag anchor limit equilibrium method and plastic limit method,and compiled the drag anchor embedded trajectory different prediction methods of calculating program.Secondly,establish finite element model for calculate the bearing capacity of drag anchor,by setting the contact pair to solve the seabed soil interaction contact friction drag anchor,anchor plate of the rectangle and use Targe169 unit simulation,soil using Conta171 unit simulation,based on the Von Mises yield criterion to establish the ideal elasticplastic model to simulate the seabed soil failure criteria,to compare the ultimate bearing capacity of the drag anchor under different conditions.Finally,the method of incremental calculation is used to establish the embedded trajectory prediction method of drag anchor,which is regarded as a continuous line segment connected from the initial embedding point down to the head and tail.In the process of incremental calculation,the ultimate bearing capacity of each incremental step towed anchor is obtained through the finite element model calculation method,which is different from the empirical coefficient method used in the NR method.At the same time,the effects of the initial embedded Angle of the drag anchor,the Angle between the anchor plate and other parameters on the embedded trajectory of the drag anchor are compared,and the specific reasons are analyzed from the perspective of ultimate bearing capacity.Through the study of this paper,it is found that the failure mode of drag anchor isdifferent in shallow and deep buried.The embedded trajectory of drag anchor is closely related to the ultimate bearing capacity of anchor plate in different buried depth.The initial embedded Angle of drag anchor has little influence on the embedding trajectory of drag anchor,and the greater the Angle between towing force and anchor plate,the greater the ultimate embedded depth of drag anchor.The embedded trajectory prediction method based on drag anchor proposed in this paper can provide reference for the trajectory prediction of drag anchor and the determination of the mooring system bearing capacity.