Proceedings of the Thirty-second (2022) International Ocean and Polar Engineering Conference
Shanghai, China, June 5–10, 2022
Copyright © 2022 by the International Society of Offshore and Polar Engineers (ISOPE)
ISBN 978-1-880653-81-4; ISSN 1098-6189

www.isope.org

An Investigation on Flexible Pipe Deformation due to Soil Displacements
Eduardo Ribeiro Malta
Civil Engineering, Memorial University of Newfoundland
St. John’s, NL, Canada
Xiaoyu Dong
Civil Engineering, Memorial University of Newfoundland
St. John’s, NL, Canada
Hodjat Shiri
Civil Engineering, Memorial University of Newfoundland
St. John’s, NL, Canadaice gouging in arctic areas and other natural phenomena. This raises theconcern of pipeline safety since failures may occur in pipelines underbending conditions, which may cause excessive tension andcompression. When compared to rigid pipes, flexible pipes have low
bending stiffness and could significantly deform and derive strengthfrom the surrounding remolded soil and adjacent undisturbed soil.
Therefore, it is of great importance to highlight the performanceverification of buried flexible pipelines exposed to large soil deformation
among the top design priorities.

ABSTRACTFlexible pipes could be used in hazardous environments for theirmechanical advantage, consisting of several different layers, eachcapable of resisting different types of loads. The long slender flexible
pipes can be self buried or intentionally buried in the seabed and beexposed to large ground movement induced by ice-gouging, landslides,and fault crossing. In these circumstances, it is of great importance toinvestigate the flexible pipe deformation and the induced stress aroundthe pipe. Whereas pipeline-soil interaction models in the literaturemainly consider a rigid pipeline section, in this paper, works considers adeformable pipeline section were conducted by developing an advanced
decoupled numerical framework, simulating a rough bore flexible pipe.
Taking advantage of Coupled Eulerian-Lagrangian (CEL) method incomputing large deformation problem and finite element models inanalyzing deformation and stress responses of multi-layer flexible pipe,
the methodology proposed in this paper is capable of estimating crosssectional deformation and local stresses, which may cause failure andsignificantly increase the risk of collapse.

The soil-pipeline interaction problem is a well-known challenge forresearch groups in both industry and academia. Theoretical andexperimental models are available to predict the ultimate lateralresistance or force-displacement responses of embedded moving
structures (e.g., ALA 2001; Martin and White 2012; Dong et al. 2021a),with some specifically focused on the trenched/backfilled pipeline-soilinteractions (e.g., Chaloulos et al. 2015; Kianian et al. 2018; Kianian andShiri 2020, 2021; Dong et al. 2021b). As in these studies, the pipeline isconsidered to be rigid and the focus is on the soil properties and themagnitude of the soil resistance. One example can be made out of Guo(2005), which focuses on retrieving the horizontal-vertical (p-q) load
space for buried pipes using a series of experiments and verifying it withcontinuum FE analyses.

KEY WORDS:
Numerical modelling; flexible pipe; pipe-soilinteraction; ABAQUS.

INTRODUCTION

Deformable pipes are considered in a few references (e.g., Lee et al.
2014; Bryden et al. 2015; Soveiti and Mosalmani 2020). Most of theseworks consider onshore water transportation installations, however
many of the techniques can be associated with offshore pipes. Lee et al.
(2015), for instance considers the concrete pipeline static and uses acontinuum FE model to verify the effects of the external pressure on theThe flexible pipes are widely used in the offshore conveying water, oil,and gas. They might be self buried in the ocean floor or trenches andbackfilled for physical protection. Those pipelines, even when buried,
are inserted in harsh environments and are constantly at risk of exposure
to large ground deformations caused by fault crossing, landslide zones,

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