The Ultimate State of Anchoring Systems from Integrated Analysis of a Plate Anchor and Mooring Line

Abstract

This paper presents a new analytical solution to predict the ultimate depth and holding capacity of plate anchors based on an integrated analysis of the anchor and mooring system. The configuration equations of the mooring line, both in soil and water, have been solved to obtain the complete line profile. A key advancement is that the mooring line angle at mudline varies compatibly with the whole anchor–mooring system. This is different from the solutions available in literature that neglect the mooring line segment in water and only assume a constant mooring line angle at the mudline. The system of equations is solved by using an iteration scheme, and parametric studies are demonstrated. The effects of line length, water depth, and seabed strength profile are explored by demonstrating the performance of a commercial plate anchor. It is found that neglecting the mooring line in water can significantly overestimate the ultimate embedment and capacity, especially when the mooring line length is relatively short. This paper can be used as an engineering tool to predict the ultimate capacity of an anchor–mooring system considering the integrated behavior of the whole system.