Finite element analysis of axial-lateral interaction behavior of buried pipelines in dense sand

Safe operation of oil and gas carrying buried pipelines and ensuring their integrity during a geohazard event are of paramount importance. Geohazards can impose a significant load on buried pipes due to the relative displacement of the surrounding soils and can increase the level of stress and strain of the pipeline in all directions. In this study, three-dimensional (3D) finite element (FE) modeling is performed to investigate the axial-lateral interaction behavior of buried pipelines in dense sand. Commercially available FE software package Abaqus/Explicit is used to accommodate the large displacement and to avoid convergence problems. In addition, a user subroutine is utilized to capture the pressure-dependent stress-strain behavior of dense sand which is usually obtained in a laboratory triaxial test. The FE model performance is verified by simulating the available experimental lateral load-displacement responses of buried pipelines in literature and the simulated results are found in good agreement with the experimental ones. Then the influences of pipe burial depth, loading angle, and pipeline surface roughness on the axial-lateral interaction behavior of buried pipelines are presented and explained with reasoning. Normalized axial-lateral interaction diagram is also proposed. One can use the results presented here to predict the axial and lateral loads on the pipeline fairly accurately for different values of pipe embedment ratio and loading angle.