Offshore pipeline buried in Indian coastal clay: buckling behaviour analysis

Abstract

Buckling is a crucial phenomenon to be considered in offshore pipelines and is dependent on the resistance of the surrounding soil, which depends on the diameter of the pipe (D) and embedment depth (H). In this study, the behaviour of the failure mechanisms and the capacity factors are investigated for a practical range of embedment depth (H) and diameter of offshore pipelines (D), using Indian coastal clay properties. A 2D plane-strain model was created using a finite element package PLAXIS 2D validated against previous studies. The immediate breakaway and no breakaway conditions are analyzed. The capacity factors are observed to increase with increasing embedment depth, up to a peak value and remain constant for further increase in embedment depth. The capacity factors are observed to be decreasing with increasing pipeline diameter. The failure mechanisms are shown using displacement contour diagrams and stress contours.