What question did this study set out to answer?

To quantify the protective performance of artificial rock-dumping layers against anchor impacts on subsea pipelines.

January 25, 2026Open Access

Experimental Investigation of the Performance of an Artificial Backfill Rock Layer Against Anchor Impacts for Submarine Pipelines

YHYang HeChina National Offshore Oil Corporation (China)CHChunhong HuChina National Offshore Oil Corporation (China)KMKunming MaChina National Offshore Oil Corporation (China)

Key Points

To quantify the protective performance of artificial rock-dumping layers against anchor impacts on subsea pipelines.
Conducted two groups of scaled model tests at a 1:15 ratio using a Hall anchor.
Measured impact forces beneath the pipeline using force sensors.
Varied backfill thicknesses and configurations during testing.
Established a safety factor baseline of 1 for bare pipes under critical velocity.
Coarse rock layers increased the safety factor to 3.69 relative to the baseline.
Multi-layer configurations elevated the safety factor to 27.
Found a non-linear relationship between backfill thickness and cushioning efficiency.

Abstract

Subsea pipelines are critical lifelines for marine resource development, yet they face severe threats from accidental ship anchor impacts. This study addresses the scientific challenge of quantifying the “protection margin” of artificial rock-dumping layers, moving beyond traditional passive structural response to a “Critical Failure Intervention” logic. Based on the energy criteria of DNV-RP-F107, a critical velocity required to trigger Concrete Weight Coating (CWC) failure for a bare pipe was derived and established as the Safety Factor baseline (S = 1). Two groups of scaled model tests (1:15) were conducted using a Hall anchor to simulate impact scenarios, where impact forces were measured via force sensors beneath the pipeline under varying backfill thicknesses and configurations. Results show that artificial backfill provides a significant protective redundancy; a 10 cm coarse rock layer increases the safety factor to 3.69 relative to the H0 baseline, while a multi-layer configuration (sand bedding plus coarse rock) elevates S to 27. Analysis reveals a non-linear relationship between backfill thickness and cushioning efficiency, characterized by diminishing marginal utility once a specific thickness threshold is reached. These findings indicate that while thickness is critical for extreme impacts, the protection efficiency optimizes at specific depths, providing a quantifiable framework to reduce small-particle layers in engineering projects without compromising safety.

KI fragen

Bookmark

View Full Paper