Impact forces of submarine landslides on offshore pipelines

Impact forces induced by submarine landslides on pipelines are estimated using a computational fluid dynamics (CFD) approach. It is found that the predicted forces using the CFD approach are consistent with those predicted using the conventional geotechnical approach. It is also found that the impact angle of the debris flow induced by landslides affects the normal drag factor but hardly has any effect on the longitudinal drag factor. Empirical formulae for estimating normal and axial impact forces on a free spanned pipeline induced by an oblique debris flow are developed based on numerical test results. A new failure envelope that can be used in conventional geotechnical approaches is also obtained based on the numerical test results.