Ice Gouging over a Buried Pipeline: Superposition Error of Simple Beam-and-Spring Models
Publication: International Journal of Geomechanics
Volume 12, Issue 4
Abstract
Two types of models, coupled and uncoupled, are currently used to determine the extent to which it is necessary to bury subsea pipelines deeper than the maximum expected depth of ice gouges. In the uncoupled model, the soil is modeled by nonlinear Winkler springs attached to the pipe at one end, with the subgouge displacement imposed at the other end of the springs. In coupled models, the soil is modeled as a three-dimensional (3D) continuum, simultaneously capturing the processes of gouging (with associated very large deformations) and the pipeline resisting the soil displacements. This paper pinpoints the main reason for differences in predictions between the coupled and uncoupled model. It is not the coupling errors (attributable to directional coupling between Winkler springs in the axial, lateral, and vertical directions, and slice-to-slice coupling), but, rather, the superposition error, which arises in the uncoupled model by adding the soil displacements attributable to the load the pipe exerts on the soil to the subgouge deformations, despite the strongly nonlinear behavior of the soil.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
The writers would like to thank C-CORE, St. Johns, NL, Canada, for permission to reproduce Fig. 1, and in particular Ryan Phillips and Michael Paulin for their help in tracing the origins of this picture. It originates from Woodworth-Lynas (1992), drawing upon submarine observations of iceberg Bertha. However, the pipeline was added later, by Desireé King. For this purpose, the ice feature was used to represent a keel rather than a berg. Otherwise, a typical pipeline would appear smaller in Fig. 1, by about a factor of 10.
References
Abdalla, B., Pike, K., Eltaher, A., Jukes, P., and Duron, B. (2009). “Development and validation of a coupled Eulerian Lagrangian finite element ice scour model.” Proc., OMAE 79553, ASME, New York.
American Lifelines Alliance (ALA). (2001). “Guidelines for design of buried steel pipelines.” ASCE/ASME Task Committee on Buried Pipelines, prepared for American Lifelines Alliance 〈www.americanlifelinesalliance.com〉 (May 4, 2012).
ASCE. (1984). Guidelines for the seismic design of oil and gas pipeline systems, ASCE Committee on Gas and Liquid Fuel Lifelines, Technical Council on Lifeline Earthquake Engineering, Reston, VA.
Bennett, R., Blasco, S., and MacKillop, K. (2007). “Seabed ice scour research in the Beaufort Sea.” Proc., PERD/CCTII Workshop, Engineering Issues for Offshore Beaufort Sea Development, Canadian Hydraulics Centre, National Research Council, Ottawa, ON, Canada.
Dassault Systèmes Simulia Corp. (Dassault). (2009). Abaqus 6.9 electronic documentation, Providence, RI.
Ju, G. T., and Kyriakides, S. (1988). “Thermal buckling of offshore pipelines.” J. Offshore Mech. Arctic Eng., 110(4), 355–364.
Konuk, I., Yu, S., and Fredj, A. (2006). “Do Winkler models work? A case study for ice scour problem.” Proc., OMAE 92335, ASME, New York.
Matlock, H., Meyer, P. L., and Holmquist, D. V. (1976). A program for discrete-element solution of axially loaded members with linear or nonlinear supports, Report to the American Petroleum Institute, Univ. of Texas at Austin, Dept. of Civil Engineering Austin, TX.
Nobahar, A., Kenny, S., King, A., McKenna, R., and Phillips, R. (2007a). “Analysis and design of buried pipelines for ice gouging hazard: A probabilistic approach.” J. Offshore Mech. Arctic Eng., 129(3), 219–228.
Nobahar, A., Kenny, S., and Phillips, R. (2007b). “Buried pipelines subject to subgouge deformations.” Int. J. Geomech., 7(3), 206–216.IJGNAI
Palmer, A. C. et al. (2003). “Uplift resistance of buried submarine pipelines: Comparison between centrifuge modelling and full-scale tests.” Géotechnique, 53(10), 877–883.GTNQA8
Palmer, A. C., Ellinas, C. P., Richards, D. M., and Guijt, J. (1990). “Design of submarine pipelines against upheaval buckling.” Proc., Offshore Technology Conference 6335, 2, American Association of Petroleum Geologists, Tulsa, OK, 551–560.
Paulin, M. J., Phillips, R., Clark, J. I., Trigg, A., and Konuk, I. (1998). “A full-scale investigation into pipeline/soil interaction.” Proc., International Pipeline Conf., ASME, Calgary, Alberta, 779–788.
Rice, J. R. (1975). “On the stability of dilatant hardening for saturated rock masses.” J. Geophys. Res., 80(11), 1531–1536.JGREA2
Vazouras, P., Karamanos, S. A., and Dakoulas, P. (2010). “Finite element analysis of buried steel pipelines under strike-slip fault displacements.” Soil Dyn. Earthquake Eng.IJDEDD, 27(3), 259–273.
Woodworth-Lynas, C. M. T. (1992). “The geology of ice scour.” Doctoral dissertation, Univ. of Wales, Cardiff, Wales.
Woodworth-Lynas, C. M. T., and Dowdeswell, J. A. (1992). “Soft-sediment striated surfaces and massive diamicton facies produced by floating ice.” Earth’s glacial record, Deynoux, M., Miller, J. M. G., Domack, E. W., Eyles, N., eds., Cambridge University Press, Cambridge, UK.
Woodworth-Lynas, C. M. T., Nixon, D., Phillips, R., and Palmer, A. (1996). “Subgouge deformations and the security of arctic marine pipelines.” Proc., Offshore Technology Conference 8222, American Association of Petroleum Geologists, Tulsa, OK.
Information & Authors
Information
Published In
Copyright
© 2012. American Society of Civil Engineers.
History
Received: Nov 18, 2010
Accepted: May 19, 2011
Published online: May 23, 2011
Published in print: Aug 1, 2012
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.