A Methodology for Estimating Anchor Penetration in Layered Soils for Cable Burial Risk Assessments

1. Home
2. Publications
3. Online Library
4. A Methodology for Estimating Anchor Penetration in Layered Soils for Cable Burial Risk Assessments

Anchors represent a significant hazard to subsea cables as they are designed to penetrate the seabed to generate sufficient holding capacity to moor vessels safely. Cable burial risk assessments (CBRA) are required in order to develop a suitable burial protection strategy for subsea cables, and this requires estimation of the potential penetration of an anchor. Where practical and technically feasible, cables are ideally located beneath the potential anchor penetration depth. Anchor penetration is a function of anchor type and size as well as the soil type and geotechnical characteristics. General anchor holding capacity estimation methods, such as the Naval Civil Engineering Laboratorys Techdata Sheet on drag embedment anchors for moorings, provide guidance on the anchor penetration trajectory for specific soil types. This may underestimate or overestimate anchor penetration as in reality the shallow geology often consists of layered sediments where the soil type and geotechnical characteristics vary with depth, thereby impacting anchor penetration trajectory. This paper presents a simplified conceptual method for estimating the anchor penetration depth in layered soils based on relationships between drag distance, holding capacity and anchor penetration for different anchor types in different soil types. Stockless, fixed, drag embedment anchors are utilized to illustrate the concept. The aim of this method is to provide a further boundary to the envelope of anchor penetration estimation to help understand the potential risk to cables and enable a more considered approach to the cable protection strategy.

5th International Symposium on Frontiers in Offshore Geotechnics (ISFOG2025)

15 - Mooring lines, Cables, Pipelines, Immersed tunnels and Risers