INFLUENCE OF LOW CONFINING PRESSURE IN MODELING OF LATERAL PIPELINE/SOIL INTERACTION IN DENSE SAND

Buried pipelines are extensively used for transporting water and hydrocarbons. Geohazards and associated ground movements represent a significant threat to pipeline integrity that may result in pipeline damage and potential failure. Safe, economic and reliable operation of pipeline transportation systems is the primary goal of the pipeline operators and regulatory agencies. The pipes are often buried at a shallow depth and therefore the behaviour of soil at low stress level need to be considered for proper modeling of the response of pipelines. In this study, finite element (FE) modeling of pipeline/soil interaction is presented, where the stress-stain behaviour of soil at low stress level is implemented. At first, triaxial test results are simulated to validate the proposed model and numerical techniques. Pipeline/soil interaction in plane strain condition is then simulated for lateral loading. The Arbitrary Lagrangian-Eulerian (ALE) method available in Abaqus/Explicit is used for FE modeling. One of the main advantages of this method is that it can simulate large deformation behaviour. The variation of non-dimensional lateral force with non-dimensional displacement is examined for different depth of embedment of pipeline and soil conditions. Finally, shear band formation in soil due to lateral movement of the pipe is presented.