FINITE ELEMENT ANALYSES OF BURIED PIPELINE SUBJECTED TO LIVE LOAD USING ABAQUS

Ahdyeh Mosadegh, Hamid Nikraz

In the proceedings of: GeoQuébec 2015: 68th Canadian Geotechnical Conference & 7th Canadian Permafrost Conference

Session: Transportation and Linear Infrastructure II / Transports et infrastructures linéaires II

ABSTRACT: This paper shows the methodology used for modelling the behaviour of a buried pipeline subjected to traffic load using the finite element method (FEM). Soil behaviour is represented by the elasto-plastic Drucker-Prager model and the pipe material is assumed to be isotropic and linear elastic using FEM software ABAQUS 6.13. For the whole system, the effect of surface pressure (magnitude of 200 and 550 kPa) on pipe-soil displacement and stress distribution is investigated at different pipe burial depths of 1-5 times the pipe diameter. In addition, the influence of pipe-soil interaction properties, boundary conditions at pipeline ends, pipe material properties and internal pressure are taken into consideration. For all cases, the results are compared with predictions obtained through numerical and experimental research, which shows satisfactory agreement with results from the literature.

RÉSUMÉ: Cet article montre la méthodologie utilisée pour modéliser le comportement d™un pipeline enfoui soumis à une charge de trafic en utilisant la méthode des éléments finis (MÉF). Le comportement du sol est représenté par le modèle élastoplastique de Drucker-Prager et le matériau du tuyau est censé être isotrope, élastique, et linéaire en utilisant le logiciel ABAQUS 6.13 de FÉM. Pour l™ensemble du système, l™effet de l™amplitude de la pression de surface (magnitude de 200 et 550 kPa) sur le déplacement tuyau-sol et sur la distribution des contraintes est étudié à différentes profondeurs d™enfouissement de 1-5 fois le diamètre du tuyau. De plus, les influences des propriétés d™interaction tuyau-sol, des conditions aux limites aux extrémités des pipelines, des propriétés du matériau du tuyau, et de la pression interne sont prises en considération. Pour tous les cas, les résultats obtenus ont été comparés avec ceux des prédictions obtenues par la recherche numérique et expérimentale, ce qui montre un accord satisfaisant avec les résultats de la littérature. 1. INTRODUCTION Pipelines are essential infrastructure for providing water and gas to urban areas. They are typically buried in onshore and offshore applications for protection. In many cases, pipelines are buried in shallow foundations under highways or railways. Any damage due to traffic load, ground movement or any other reason can cause failure in the pipeline or malfunctioning of the system. In recent decades, many numerical and experimental studies have investigated the response of buried pipes subjected to different conditions focusing on pipe-soil interaction. In the 1970s, pipe-soil interaction analysis received attention from many researchers. For numerical studies, the American Concrete Pipe Association made a serious study of buried concrete pipe behaviour using a finite element method (FEM) computer programme. The use of FEM to simulate problems was introduced by Culvert in 1976, and in 1984 ASCE introduced the Winkler model, an elasto-plastic soil spring model based on the model developed by Audibert (Audibert and Nyman 1977). Since then, many numerical and experimental analyses have been performed to investigate buried pipe response under various conditions such as moisture change, cyclic load, installation procedure effects and so on (Abo-Elnor et al. 2004; Calvetti et al. 2004; Chatterjee et al. 2013; Farhadi Hikooei 2013; Kang et al. 2008; Liu et al. 2010; Rajeev and Kodikara 2011; Trautmann 1985; Zaman M M et al. 1984). Various numerical and experimental researches have investigated the effect of various parameters on pipeline behaviour using different approaches. In a numerical study the effect of interaction properties, backfill geometry and material properties on pipe-soil interaction was investigated using the FEM software ABAQUS (Kararam 2006). It was found that increasing the friction coefficient leads to a reduction in pipe deflection and the effect of bedding material is more significant than the effect of bedding thickness on induced stress. In another study, the behaviour of an HDPE pipe buried in a sandy soil under cyclic load was analysed through an experimental approach (Tafreshi and Khalaj 2011). A formulation was developed to calculate soil surface settlement and pipe crown displacement based on soil density, burial depth variation and stress. It was found that burial depth, amplitude of surface pressure and soil density dramatically affects pipe behaviour. The results from this research showed that increasing the burial depth leads to an increase in soil settlement and a decrease in pipe displacement. Also increasing the burial depth leads to a considerable reduction in the rate of pipe displacement conducted another investigation in which a steel pipe was subjected to a repeated load up to 100 kPa(Mir Mohammad Hosseini and Moghaddas Tafreshi 2002). It was found that pipe embedment depth and soil density were the most significant parameters, amongst others. Another study considered the effect of various conditions on pipe-soil interaction subjected to a surface surcharge load. Soil and pipe were modelled as a continuous area with two different nodes and their interaction modelled as a surface to node. The researchers found that the impact of bedding stiffness and compaction levels on the induced

Please include this code when submitting a data update: GEO2015_446

Access this article:
Canadian Geotechnical Society members can access to this article, along with all other Canadian Geotechnical Conference proceedings, in the Member Area. Conference proceedings are also available in many libraries.

Cite this article: