A Review of Drag Anchor Penetration Models to Inform Cable Burial Risk Assessment-Paper

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The paper reviews methods for predicting drag-anchor penetration, an important factor in setting burial depths for subsea power cables exposed to anchor strikes. It focuses on anchor trajectory and kinematics, rather than the shape and forces of the installation line, and mainly considers routine anchoring; emergency anchoring is less predictable and may involve little embedment and substantial dragging.<br /><br />Analytical approaches fall into four groups: limit equilibrium methods, yield-envelope formulations, limit analysis, and kinematic-enforcement models. They offer practical ways to estimate anchor movement and ultimate embedment, but rely on assumptions and parameters that can be difficult to determine, including soil bearing-capacity factors and the anchor’s movement direction. Yield-envelope methods may be more reliable but are computationally demanding. The reviewed models are mostly restricted to clay or two-dimensional analyses, leaving important gaps, particularly for sandy soils and three-dimensional effects.<br /><br />Numerical modelling using the coupled Eulerian–Lagrangian (CEL) method can handle the large soil deformations that challenge conventional finite-element methods. Simulations have examined anchors in clay and sand, including emergency conditions, but some reported behaviours differ markedly from earlier findings and need further investigation. Laboratory and field tests help validate models and reveal the influence of soil conditions, anchor geometry, installation lines, and deployment circumstances. Field tests under emergency-like conditions have sometimes found much less penetration than standard models predict.<br /><br />Overall, existing research provides a useful foundation for assessing anchor penetration and cable-burial risk, but prediction uncertainty remains. Further validation, comparisons between numerical methods, and improved treatment of soil type, anchor geometry, and emergency deployment are needed to support more reliable and economical burial-depth decisions.

Keywords

drag-anchor penetration

subsea power cables

anchor strike

burial depth

anchor trajectory

kinematics

soil mechanics

CEL method

yield-envelope

anchor embedment