Effect of drag rates on drag embedment anchor penetration for cable burial risk assessment

Michael Brown; Yaseen Sharif; Robert E. Bird; William M. Coombs; Charles Augarde; Catriona Macdonald; Duncan Stevens

doi:10.1680/jgele.25.00069

Effect of drag rates on drag embedment anchor penetration for cable burial risk assessment

Michael Brown
, Yaseen Sharif
, Robert E. Bird
, William M. Coombs
, Charles Augarde
, Catriona Macdonald
, Duncan Stevens

Civil Engineering

Research output: Contribution to journal › Article › peer-review

2 Citations (Scopus)

51 Downloads (Pure)

Abstract

Cable burial risk assessment (CBRA) defines minimum seabed burial depth of cables to avoid interaction with towed objects that penetrate the seabed e.g. drag embedment anchors (DEA). Recent physical modelling studies have shown that model anchors are dragged dry sand may penetrate to much greater depths in loose sand than current CBRA approaches predict. As other seabed penetrating objects (e.g. pipeline ploughs) have shown velocity or rate of pull dependant behaviour in saturated soils it is necessary to check for similar rate dependant penetration behaviour for DEAs. This is required to verify the effect of anchor drag rates in CBRA methods and the validity of previous modelling studies that differ in their findings from current CBRA. This study used model centrifuge tests of DEAs pulled at varying rates in saturated conditions. The result show that anchor penetration depths are reduced with increasing drag rates. The results also confirm that CBRA assumptions of anchor orientation are not consistent with observed behaviour and soil penetration factors require updating. The results suggest that CBRA approaches should also consider the drag speed of the penetration event as this may vary during emergency deployment or may be much lower where a vessel drifts at anchor.

Original language	English
Number of pages	5
Journal	Geotechnique Letters
Early online date	16 Dec 2025
DOIs	https://doi.org/10.1680/jgele.25.00069
Publication status	E-pub ahead of print - 16 Dec 2025

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

SDG 7 Affordable and Clean Energy
SDG 9 Industry, Innovation, and Infrastructure

Keywords

Drag embedment anchors
Rate effects
Cable Burial Risk Assessment
Centrifuge modelling
Geotechnical engineering
Models (physical)
Offshore renewable energy
Sands
offshore renewable energy
anchors and anchorages

ASJC Scopus subject areas

Civil and Structural Engineering
Renewable Energy, Sustainability and the Environment
Geotechnical Engineering and Engineering Geology

Access to Document

10.1680/jgele.25.00069

Author Accepted ManuscriptAccepted author manuscript, 11.9 MBLicence: CC BY

1 Finished

Offshore Cable Burial: How deep is deep enough? (Joint with Durham University and British Geological Survey)
Brown, M. (Investigator)
1/02/22 → 31/03/26
Project: Research

2 Citations
5 Article
4 Conference contribution
3 Paper
1 Commissioned report
More
- 1 Other report

Characterising shallow subsurface variability in the UK North Sea: a regional analysis using geotechnical records
Macdonald, C., Stevens, D., Carter, G., Johnson, K., Coombs, W. M., Bird, R. E., Augarde, C., Brown, M. & Sharif, Y., 5 Jul 2026, British Geological Survey. 39 p.
Research output: Book/Report › Other report
Drag embedment anchor penetration in layered sands and through cable and pipeline trenches
Sharif, Y., Brown, M. (Lead / Corresponding author), Stevens, D., Bird, R. E., Coombs, W. M., Augarde, C. & Macdonald, C., 30 Aug 2026, In: Ocean Engineering. 364, 1, 11 p., 126853.
Research output: Contribution to journal › Article › peer-review

Open Access
File
5 Downloads (Pure)
Three-dimensional modelling of drag anchor penetration using the material point method
Bird, R. E., Coombs, W. M. (Lead / Corresponding author), Brown, M., Augarde, C., Sharif, Y., Pretti, G., Macdonald, C., Stevens, D. & Carter, G., 15 Jun 2026, In: Ocean Engineering. 358, 2, 125456.
Research output: Contribution to journal › Article › peer-review

Open Access
File
11 Downloads (Pure)

4 Invited talk
1 Keynote

Invited presentation: NEXANS Lunch & Learn, Cable Protection Teams European Subsea Cables Association, Cable Burial Risk Assessment (CBRA) Modelling.
Brown, M. (Speaker) & Coombs, W. M. (Speaker)
27 Jan 2026
Activity: Talk or presentation types › Invited talk
Invited presentation: European Subsea Cables Association, Renewables and Power Cables Subgroup (RPSG), Cable Burial Risk Assessment (CBRA) Modelling
Brown, M. (Speaker) & Coombs, W. M. (Speaker)
11 Sept 2025
Activity: Talk or presentation types › Invited talk
Keynote Lecture: 2nd Offshore Wind Symposium: Cables, pipelines and shallow infrastructure installation, Geological Society Energy Group: Physical and numerical modelling of drag anchor penetration: assessing seabed penetration factors to inform depth of lowering of subsea cables
Coombs, W. M. (Speaker) & Brown, M. (Speaker)
19 Sept 2025
Activity: Talk or presentation types › Keynote

A Ghost Ship’s Doomed Journey Through the Gate of Tears
Brown, M.
1/04/24
1 Media contribution
Press/Media: Research

Institution of Civil Engineers Physical Modelling Prize 2026
Sharif, Y. (Recipient), Brown, M. (Recipient), Knappett, J. (Recipient), Davidson, C. (Recipient), Bird, R. E. (Recipient), Coombs, W. M. (Recipient), Augarde, C. (Recipient), Carter, G. (Recipient), Macdonald, C. (Recipient) & Johnson, K. (Recipient), 27 Apr 2026
Prize: Prize (including medals and awards)

Cite this

@article{ac156184d9084bfbab0530cdbb36bdb0,

title = "Effect of drag rates on drag embedment anchor penetration for cable burial risk assessment",

abstract = "Cable burial risk assessment (CBRA) defines minimum seabed burial depth of cables to avoid interaction with towed objects that penetrate the seabed e.g. drag embedment anchors (DEA). Recent physical modelling studies have shown that model anchors are dragged dry sand may penetrate to much greater depths in loose sand than current CBRA approaches predict. As other seabed penetrating objects (e.g. pipeline ploughs) have shown velocity or rate of pull dependant behaviour in saturated soils it is necessary to check for similar rate dependant penetration behaviour for DEAs. This is required to verify the effect of anchor drag rates in CBRA methods and the validity of previous modelling studies that differ in their findings from current CBRA. This study used model centrifuge tests of DEAs pulled at varying rates in saturated conditions. The result show that anchor penetration depths are reduced with increasing drag rates. The results also confirm that CBRA assumptions of anchor orientation are not consistent with observed behaviour and soil penetration factors require updating. The results suggest that CBRA approaches should also consider the drag speed of the penetration event as this may vary during emergency deployment or may be much lower where a vessel drifts at anchor.",

keywords = "Drag embedment anchors, Rate effects, Cable Burial Risk Assessment, Centrifuge modelling, Geotechnical engineering, Models (physical), Offshore renewable energy, Sands, offshore renewable energy, anchors and anchorages",

author = "Michael Brown and Yaseen Sharif and Bird, \{Robert E.\} and Coombs, \{William M.\} and Charles Augarde and Catriona Macdonald and Duncan Stevens",

year = "2025",

month = dec,

day = "16",

doi = "10.1680/jgele.25.00069",

language = "English",

journal = "Geotechnique Letters",

issn = "2045-2543",

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}

TY - JOUR

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AU - Brown, Michael

AU - Sharif, Yaseen

AU - Bird, Robert E.

AU - Coombs, William M.

AU - Augarde, Charles

AU - Macdonald, Catriona

AU - Stevens, Duncan

PY - 2025/12/16

Y1 - 2025/12/16

N2 - Cable burial risk assessment (CBRA) defines minimum seabed burial depth of cables to avoid interaction with towed objects that penetrate the seabed e.g. drag embedment anchors (DEA). Recent physical modelling studies have shown that model anchors are dragged dry sand may penetrate to much greater depths in loose sand than current CBRA approaches predict. As other seabed penetrating objects (e.g. pipeline ploughs) have shown velocity or rate of pull dependant behaviour in saturated soils it is necessary to check for similar rate dependant penetration behaviour for DEAs. This is required to verify the effect of anchor drag rates in CBRA methods and the validity of previous modelling studies that differ in their findings from current CBRA. This study used model centrifuge tests of DEAs pulled at varying rates in saturated conditions. The result show that anchor penetration depths are reduced with increasing drag rates. The results also confirm that CBRA assumptions of anchor orientation are not consistent with observed behaviour and soil penetration factors require updating. The results suggest that CBRA approaches should also consider the drag speed of the penetration event as this may vary during emergency deployment or may be much lower where a vessel drifts at anchor.

AB - Cable burial risk assessment (CBRA) defines minimum seabed burial depth of cables to avoid interaction with towed objects that penetrate the seabed e.g. drag embedment anchors (DEA). Recent physical modelling studies have shown that model anchors are dragged dry sand may penetrate to much greater depths in loose sand than current CBRA approaches predict. As other seabed penetrating objects (e.g. pipeline ploughs) have shown velocity or rate of pull dependant behaviour in saturated soils it is necessary to check for similar rate dependant penetration behaviour for DEAs. This is required to verify the effect of anchor drag rates in CBRA methods and the validity of previous modelling studies that differ in their findings from current CBRA. This study used model centrifuge tests of DEAs pulled at varying rates in saturated conditions. The result show that anchor penetration depths are reduced with increasing drag rates. The results also confirm that CBRA assumptions of anchor orientation are not consistent with observed behaviour and soil penetration factors require updating. The results suggest that CBRA approaches should also consider the drag speed of the penetration event as this may vary during emergency deployment or may be much lower where a vessel drifts at anchor.

KW - Drag embedment anchors

KW - Rate effects

KW - Cable Burial Risk Assessment

KW - Centrifuge modelling

KW - Geotechnical engineering

KW - Models (physical)

KW - Offshore renewable energy

KW - Sands

KW - offshore renewable energy

KW - anchors and anchorages

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DO - 10.1680/jgele.25.00069

M3 - Article

SN - 2045-2543

JO - Geotechnique Letters

JF - Geotechnique Letters

ER -

Effect of drag rates on drag embedment anchor penetration for cable burial risk assessment

Abstract

UN SDGs

Keywords

ASJC Scopus subject areas

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Cite this