Localised upheaval buckling of buried subsea pipelines
Z.K. Wang, G.H.M. van der Heijden & Y.G. Tang
Buried subsea pipelines under high temperature conditions tend to relieve
their axial compressive force by forming localised upheaval buckles. This
phenomenon is traditionally studied as a kind of imperfect column buckling
problem. We study upheaval buckling as a genuinely localised buckling
phenomenon without making any ad hoc assumptions on the shape of the buckled
pipeline. We combine this buckling analysis with a detailed state-of-the-art
nonlinear pipe-soil interaction model that accounts for the effect of uplift
peak soil resistance for buried pipelines. This allows us to investigate the
effect of cover depth of subsea pipelines on their load-deflection behaviour.
Furthermore, the influence of axial and uplift peak soil resistance on the
localised upheaval behaviour is investigated and the maximum axial
compressive stress during the buckling process is discussed. Parameter
studies reveal a limit to the temperature difference for safe operation of
the pipeline. Localised upheaval buckling may then occur if the pipe is
sufficiently imperfect or sufficiently dynamically perturbed.
keywords: buried subsea pipelines, localised upheaval buckling, nonlinear
pipe-soil interaction model
Marine Structures 60, 165-185 (2018)