Ovalization of steel energy pipelines buried in saturated sands during ground deformations

Cross-sectional ovalization of buried steel pipes subjected to bending moment induced by end displacements is discussed. A three dimensional finite element analysis was conducted employing Abaqus/CAE. The pipe was simulated using 3D shell elements while the saturated sand soil medium was simulated by employing discrete nonlinear springs along the pipeline. The effects of normalized burial depth (H/D), diameter to wall thickness ratio (D/t), sand density and level of the internal pressure on the ovalization are investigated, and resulting ovalization distribution with respect to bending moment at critical sections is presented. The results of this study enable simple one dimensional finite element models to consider geometrical cross-sectional nonlinearities in the analysis of buried pipelines.