Localised lateral buckling of partially embedded subsea
pipelines with nonlinear soil resistance
Z.K. Wang & G.H.M. van der Heijden
Unburied partially embedded subsea pipelines under high temperature
conditions tend to relieve their axial compressive force by forming
localised lateral buckles. This phenomenon is traditionally studied as a
kind of imperfect column buckling problem. We study lateral buckling as a
genuinely localised buckling phenomenon governed by a different static
instability, with a different critical load. No ad hoc assumptions need to
be made. We combine this buckling analysis with a detailed state-of-the-art
nonlinear pipe-soil interaction model that accounts for the effect of lateral
breakout resistance. This allows us to investigate the effect of initial
embedment of subsea pipelines on their load-deflection behaviour. Parameter
studies reveal a limit to the temperature difference for safe operation of
the pipeline, in the sense that for higher temperature differences a
localised buckling mode has lower total energy than the straight unbuckled
pipe. Localised lateral buckling may then occur if the pipe is sufficiently
imperfect or sufficiently dynamically perturbed.
Thin-Walled Structures 120, 408-420 (2017)