An Approximate Procedure for Assessing the Effects of Mudslides on Offshore Pipelines

The theoretical basis of an approximate procedure for assessing the effects of mudslides on buried marine pipelines is presented. The procedure has the capability to account for geometric nonlinearities (i.e., large-displacement “cablelike” behavior of the pipeline), nonlinear longitudinal soil restraint against pipeline pull-out, and a limited degree of nonlinear pipe material behavior. The analytical approach is based upon a variational work method known as the Theorem of Stationary Total Potential and is simpler and easier to employ than a nonlinear finite element code, while generally yielding good approximations to pipeline stresses and strains. The validity of the procedure is demonstrated for a typical mudslide situation through comparison with results of nonlinear finite element analyses.