Buried pipelines, used for transporting liquid and gas, are often subjected to axial pulling forces due to seasonal temperature changes and/or relative ground movements. The axial pullout force is ...
This paper describes a full-scale laboratory study of the axial sliding behaviour of a trenched pipeline surrounded by sand backfill. Cyclic axial displacements are applied to a heavy pipe buried in a narrow trench (less than three pipe diameters wide), using various backfill cover depths and two different soils: dry Hostun sand and a damp, silty sand. A novel testing tank is employed, with compressible foam seals to allow the pipe to settle as it moves axially, and a pressure bag system to simu...
Finite element (FE) analyses of pipeline–soil interaction for pipelines buried in dense sand subjected to lateral ground displacements are presented in this paper. Analysis is performed — using the Arbitrary Lagrangian–Eulerian (ALE) method available in Abaqus/Explicit FE software — in the plane strain condition using the Mohr–Coulomb (MC) and modified Mohr–Coulomb (MMC) models. The MMC model considers a number of important features and properties of stress–strain and volume change behaviour of ...
AbstractThis paper describes finite-element (FE) modeling, validated by large-scale tests, to simulate the lateral force versus displacement relationship of pipelines under plane-strain conditions in both dry and partially saturated sand. The FE model is based on an elastoplastic characterization of the soil, with Mohr-Coulomb strength parameters to determine the soil yield surface. Direct shear test data and strain softening models are used to represent peak and postpeak strength behavior. A me...
This paper presents results from an experimental and numerical study on the axial–lateral interaction of pipes with dense sand. A series of centrifuge tests were conducted, with a rigid pipeline displaced in the horizontal plane in a cohesionless test bed. The relative pipe–soil interaction included axial, lateral, and oblique loading events. A three-dimensional continuum finite element model was developed using ABAQUS/Standard (Hibbitt et al. 2005) software. The numerical model was calibrated a...
Cast iron pipe came into heavy use during the latter half of the 19th century and numerous utility companies formed extensive pipeline networks using cast iron pipes until 1940s. Later cast iron pipe was superseded by ductile iron pipe. The existing cast iron pipelines have been in service for a long period of time, with some of them being more than a century old. While many of the existing cast iron pipelines remain perfectly serviceable, some of them show signs of deterioration, mainly in the ...
The performance of buried steel pipelines subjected to relative soil movements in the axial direction was investigated using full-scale pullout testing in a soil chamber. Measured axial soil loads from pullout testing of pipes buried in loose dry sand were comparable to those predicted using guidelines commonly used in practice. The peak values of axial pullout resistance observed on pipes buried in dense dry sand were several-fold (in excess of 2 times) higher than the predictions from guidelin...
The performance of buried, medium-density polyethylene (MDPE) pipes subject to movements relative to the soil in the direction of the pipe axis is investigated by full-scale physical model testing conducted using a large soil box. A new closed-form solution was developed to account for the nonlinear material response of MDPE pipes under axial loading, and the analytical results are compared with the results obtained from the full-scale pipe pullout testing. The closed-form solution provides a ra...
This paper investigates the pipe.soil interaction for pipes buried in cohesionless soil when subjected to lateral ground movement. A review and reappraisal of the literature is conducted to identify some inconsistencies and shortcomings of previous studies. The effects of model scale, stress level (via burial depth), burial depth ratio, and soil properties are systematically addressed through finite element analyses. The study concludes that the effects of pipe size and burial depth must be take...
The soil–pipeline interactions in sand under lateral and upward movements are investigated with particular attention to the peak forces exerted on the pipe. The analytical solutions for estimating the peak forces are summarized and it is shown that, for deep embedment condition, there is large uncertainty in the true values since the bounds established by the analytical solutions are large. In order to find the solution for the peak force and to investigate its transition from shallow to deep fa...
Estimation of the axial capacity of piles driven into sand involves considerable uncertainty, and design rules are generally not consistent with the physical processes involved. This Paper reviews current understanding of the factors that determine the axial capacity of piles driven into sand, and outlines a new framework for design which takes account of the physical processes, is consistent with the existing database of load test results, and is sufficiently flexible to permit refinement as ne...
Abstract This paper presents an experimental investigation into the axial pullout behavior of buried medium-density polyethylene (MDPE) pipes under various pulling rates. Tests were conducted in a ...