Three-Dimensional Large Deformation Analyses of Plate Anchor Keying in Clay

Plate anchors are a relatively new type of offshore anchorage in deep water. Plate anchors are usually installed vertically, followed by rotation under eccentric pulling force. In normally consolidated clay, the embedment loss during keying may reduce the anchor capacity significantly. The keying behaviour of rectangular anchors is investigated here using a three-dimensional large deformation finite element approach. This approach adopts mesh regeneration to avoid severe distortion of soil elements, as well as mapping the stresses and material parameters from the old to the new mesh. To study the factors affecting the embedment loss, the loading eccentricity ratio was varied from 0.17 to 1.5 for aspect ratios of the anchors of 1 and 2. The strength profile and rigidity of soil and loading orientation were also varied. The numerical results agree well with centrifuge testing data. It is found the embedment loss depends strongly on the eccentricity ratio and orientation of pulling force, while the effects of soil rigidity and anchor aspect ratio are minimal.