A Method to Predict Embedded Trajectory Based on the Finite Element Analyses of Bearing Capacity of Drag Anchor

Abstract

With the development of marine resources going to deeper water depth, the mooring system design becomes more important. Predicting the embedded trajectory of drag anchor during the installation process is very significant for calculating the ultimate pullout bearing capacity of drag anchor and the mooring system design. Firstly, the initial angle and embedded depth of drag anchor are assumed. Secondly, the drag anchor penetrates a unit displacement along the direction parallel to the anchor fluke at each incremental step, and the specific position information (horizontal, vertical, angle) could be obtained. Thirdly, the ultimate bearing capacity of drag anchor at this incremental step could be calculated using the two-dimensional and three-dimensional finite element model which considering the contact friction between the drag embedment anchor and seabed clay. And then, the new specific position information could be obtained according to the mechanical equilibrium equation of inverse catenary. Finally, the whole drag anchor embedded trajectory could be obtained when the drag angle between the anchor fluke and seabed tends to zero as a limit state. In this paper, a method of predicting embedded trajectory based on the finite element analyses of bearing capacity of drag anchor is established, which could be used as a reference for the practical engineering.