Keying process of a novel folding-plate anchor: investigation of installation depth loss

As marine resource exploitation advances into deep sea, existing mooring anchors require optimized design to achieve higher bearing capacity, more convenient installation method, and more precise positioning to meet engineering requirements. This study proposes a novel folding-plate anchor (FPA). An FPA consists of two folding plates attached to a mounting block via hinges. The plates remain folded during installation to reduce soil resistance, and then deploy after the keying process to provide maximum load capacity. In shallow water, the FPA can be installed using static press-in methods, whereas in deep water, it can be dynamically installed under their own gravity. However, the depth loss during the keying process can significantly affect its bearing performance. This study employed validated coupled Eulerian-Lagrangian modeling to systematically evaluate the pretension characteristics of the novel FPA. Depth loss during the pretension process was assessed, and the strain characteristics of the folding plates during rotational unfolding and the soil mobilization mechanism were revealed. It is found that the depth loss during pretension ranges from 1.0 to 1.4 times the plate length. An annular flow zone gradually forms around the folding plate during unfolding. Total soil resistance mobilized during pretension accounts for approximately one-third of the ultimate capacity under service conditions. These findings provide valuable reference for the design and application of novel FPAs. • Propose a novel folding-plate anchor (FPA) with plates folded during installation and deployed after keying. • Adopt a large-deformation model to simulate the FPA keying process and evaluate penetration depth loss. • Investigate the effects of key factors on depth loss, including undrained shear strength, folding-plate geometry, and deployment angle.