The Asynchronous Installation Effect on the Embedment Performance and Dynamic Response of a Novel Group-Drag-Anchor System in a Soft Clay Seabed

A novel group-drag-anchor system (GDAS), comprising a Delta anchor and a four-tooth anchor, was developed to enhance mooring capacity for floating offshore wind turbines in soft clay seabeds. This study focuses on the influence of the installation method on the embedment performance and dynamic response of the GDAS. Large-deformation finite element analyses were conducted using the coupled Eulerian–Lagrangian (CEL) technique to simulate the installation process under different configurations. A dedicated subroutine was implemented to monitor the evolution of excess pore pressure around the GDAS during the subsequent dynamic loading. Results show that asynchronous installation yields significantly deeper embedment than synchronous installation, especially in seabeds with steep strength gradients. The dynamic response of the GDAS under wave-only, combined wave–current, and mooring-line-failure loading scenarios was further investigated. The asynchronously installed GDAS exhibits considerably more stable long-term performance and lower risk of progressive failure under extreme environmental conditions. This superiority is most evident in clays with a relatively steep strength gradient. These findings provide valuable guidance for the optimal design and installation sequencing of GDASs in engineering practice.