The drag effects on the penetration behavior of drag anchors during installation

The penetration behavior of drag anchors in the seabed is directly controlled by the anchor handling vessel (AHV) and the installation line. However, the drag effects produced by the AHV and the installation line are difficult to investigate by either theoretical or experimental methods. In the present work, a large deformation numerical analysis employing the coupled Eulerian-Lagrangian technique is performed to investigate the effects of the drag velocity of AHV, the uplift angle of installation line, the diameter of installation line, and the length of installation line. It is demonstrated that the movement direction and the drag angle at the shackle of the anchor are not influenced by drag effects, while the drag effects on the anchor trajectory and the drag force are significant. Findings of the present study also yield a relation between drag velocity and drag force and the knowledge of the ultimate embedment depth of anchor and the critical length of installation line, which are beneficial to fully understanding the drag embedment problems and to enhancing the installation techniques for drag anchors.