Centrifuge modelling of the upheaval capacity of pipelines in liquefied clay

M. F. Bransby, T. A. Newson, P. Brunning

    Research output: Contribution to conferenceConference presentation/ephemera

    12 Citations (Scopus)

    Abstract

    Offshore pipelines are often placed in the seabed by 'jetting' the soil to soften it and allow pipeline penetration. In this paper, it is shown that this has implications for the resistance of the soil to upwards pipeline movements caused by pipeline temperature changes (upheaval buckling). To investigate this, a series of centrifuge model tests have been conducted to investigate the uplift capacity and the load-displacement behaviour of pipelines buried in recently liquefied clay. Both short and long-term loadings are considered. The undrained uplift capacities were seen to be lower than the drained capacity so that it was the undrained failure conditions that was critical. Recently liquefied clay may still be consolidating when pipelines are commissioned and are subject to upheaval loads. In such cases, the effective stresses in the soil (and thus the shear strengths) at the expected switch-on time have to be calculated in order to calculate the uplift capacity of the pipeline. A simple method is presented which predicts uplift capacity from the average degree of consolidation of the backfill. Good comparison between the experimental results and the simple prediction method suggests that such a method may be appropriate for initial pipeline design.

    Original languageEnglish
    Pages100-107
    Number of pages8
    Publication statusPublished - 1 Dec 2002
    EventProceedings of the Twelfth (2002) International Offshore and Polar Engineering Conference - Kitakyushu, Japan
    Duration: 26 May 200231 May 2002

    Conference

    ConferenceProceedings of the Twelfth (2002) International Offshore and Polar Engineering Conference
    CountryJapan
    CityKitakyushu
    Period26/05/0231/05/02

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  • Cite this

    Bransby, M. F., Newson, T. A., & Brunning, P. (2002). Centrifuge modelling of the upheaval capacity of pipelines in liquefied clay. 100-107. Paper presented at Proceedings of the Twelfth (2002) International Offshore and Polar Engineering Conference, Kitakyushu, Japan.