Effects of Slope Grade on Soil-Pipe Interaction: Full-Scale Experiments

2020 ◽  
Author(s):  
Mohammad Katebi ◽  
Dharma Wijewickreme ◽  
Pooneh Maghoul ◽  
Kshama Roy
Keyword(s):  
Practice Guidelines ◽  
Ground Surface ◽  
Full Scale ◽  
Mountainous Areas ◽  
Buried Pipelines ◽  
Sloping Ground ◽  
Physical Model Tests ◽  
Industry Practice ◽  
Surface Inclination ◽  
Soil Pipe

Abstract In the current industry practice guidelines, the soil restraints to assess the behaviour of pipelines subject to permanent ground displacements are numerically characterized using independent “soil springs”. These guidelines have been primarily generated by considering the typical configurations of buried pipelines in level ground. The assumption of level ground does not always hold true when assessing pipelines located on sloping ground in mountainous areas and riverbanks. This research presents the outcomes from a set of full-scale physical model tests conducted on a pipe buried in slopes. The results highlight the significance of the slope grade effects on soil-pipe interaction. The results are useful as input to modify soil springs accounting for the ground surface inclination.

Soil-Pipe Interaction Models for the Simulation of Buried Steel Pipeline Behaviour Against Geohazards

2017 ◽  
Author(s):  
Gregory C. Sarvanis ◽  
Spyros A. Karamanos ◽  
Polynikis Vazouras ◽  
Panos Dakoulas ◽  
Elisabetta Mecozzi ◽  
...  
Keyword(s):  
Structural Integrity ◽  
Experimental Testing ◽  
Complex Loading ◽  
Full Scale ◽  
Design Calculation ◽  
Analytical Methodology ◽  
Interaction Models ◽  
Rigorous Model ◽  
Pipeline Design ◽  
Soil Pipe

Hydrocarbon pipelines constructed in geohazards areas, are subjected to ground-induced actions, associated with the development of severe strains in the pipeline and constitute major threats for their structural integrity. In the course of pipeline design, calculation of those strains is necessary for safeguarding pipeline integrity, and the development of reliable analytical/numerical design tools that account for soil-pipe interaction is required. In the present paper, soil-pipe interaction models for buried steel pipelines subjected to severe ground-induced actions are presented. First, two numerical methodologies, (simplified and rigorous) and one analytical are presented and compared, followed by an experimental verification; transversal soil-pipe interaction is examined through full-scale experimental testing, and comparisons of numerical simulations with rigorous finite element models are reported. Furthermore, the rigorous model is compared with the results from a special-purpose full-scale “landslide/fault” experimental test in order to examine the soil-pipe interaction in a complex loading conditions. Finally, the verified rigorous model is compared with both the simplified models and the analytical methodology.

Development of Soil Restraints for Buried Pipelines in Muskeg Soils Subjected to Lateral Ground Displacements

2020 ◽  
Author(s):  
Dharma Wijewickreme ◽  
Thushara Jayasinghe
Keyword(s):  
Constitutive Model ◽  
Numerical Models ◽  
Field Testing ◽  
Soil Mass ◽  
Systematic Research ◽  
Cone Penetration ◽  
Buried Pipelines ◽  
Penetration Testing ◽  
Cone Penetration Testing ◽  
Soil Pipe

Abstract A systematic research program was undertaken with the objective of developing quantitative geotechnical parameters to support soil-pipe interaction assessment for buried pipelines in muskeg. For this purpose, a field geotechnical investigation program comprising cone penetration testing (SCPT) with shear wave velocity (Vs) measurements, electronic field vane shear testing (eVST), full-flow ball penetration testing (BPT), and pressuremeter testing (PMT), along with fixed-piston tube soil sampling was undertaken in a muskeg soil terrain. The data from field testing were initially interpreted to obtain typical stiffness and strength parameters for the subject soils. These parameters were then used to numerically simulate pressuremeter tests and the results were compared with those obtained from field pressuremeter testing; the intent was to calibrate a suitable constitutive model to represent the muskeg soil mass. These ascalibrated constitutive model was then applied on numerical models developed to simulate buried pipelines in muskeg soil subject to relative lateral ground movements. The work is aimed at developing a framework to generate soil restraint versus relative ground displacement relations (“soil springs”) to assess soil-pipe interaction of pipelines buried in muskeg soils. Initial results from the research are presented herein, with a comparison made between soil springs developed from numerical analyses and those generated from current practice guidelines.

Development of a Pipeline Surface Loading Screening Process

2006 ◽  
Author(s):  
David J. Warman ◽  
Jules Chorney ◽  
Mike Reed ◽  
James D. Hart
Keyword(s):  
Ground Surface ◽  
Theoretical Models ◽  
Operating Pressure ◽  
Initial Screening ◽  
Buried Pipelines ◽  
Surface Loading ◽  
Design Factor ◽  
Screening Process ◽  
Simplified Approach ◽  
Design Basis

Pipeline Operators receive numerous requests annually to cross their pipelines. In many of these cases detailed analysis using a number of different methods are performed since no simplified approach is available. The Canadian Energy Pipeline Association (CEPA) with Kiefner and Associates, Inc. undertook the development of a screening methodology for vehicle loading. The hope is a standard approach to these analyses might be established to assist pipeline operating companies. This paper describes an approach detailing the development and implementation of a simplified screening process to assess the effects of surface loads on buried pipelines. A design basis was established based on a literature review to identify theoretical models, standards, codes, and recommended practices that are currently used to assess the surface loading effects on buried pipelines. This design basis was incorporated into a methodology utilized to develop a screening tool which provides a simple “pass/no pass” determination and is based on attributes which are generally easy to obtain (e.g., wheel or axle load, ground surface loading pressure, depth of cover, maximum allowable operating pressure and design factor). Situations which pass the initial screening would require no additional analysis while situations that do not pass the initial screening may need to be evaluated on a more detailed basis. Simplified graphs have been developed to assist in additional screening prior to performing a more detailed evaluation.

scholarly journals Full-depth avalanche occurrences caused by snow gliding, Coquihalla, British Columbia, Canada

1999 ◽  
Vol 45 (151) ◽  
pp. 539-546 ◽  
Author(s):  
Jennifer Clarke ◽  
David McClung
Keyword(s):  
British Columbia ◽  
Stainless Steel ◽  
Ground Surface ◽  
Free Water ◽  
Important Influence ◽  
Reliable Indicator ◽  
Climate Data ◽  
Cascade Mountains ◽  
Sloping Ground ◽  
Snow Gliding

AbstractSnow glide is the translational slip of the entire snowpack over a sloping ground surface, and it is thought that rapid rates of snow glide precede full-depth avalanches. The nature of avalanches that release at the ground makes them difficult to predict and difficult to control using explosives.On-slope instrumentation comprised of stainless-steel "glide shoes" was used to measure rates of snow glide for two winters on a bedrock slope adjacent to the Coquihalla Highway, Cascade Mountains, British Columbia, Canada. Climate data and avalanche occurrences were recorded by the British Columbia Ministry of Transportation and Highways.Our results show that the supply of free water to the snow/ground interface by rain or snowmelt is the most important influence on full-depth avalanche release. Full-depth avalanche release responds to rainfall and snowmelt events within 12-24 hours. Occasionally, full-depth avalanches occur unexpectedly during clear, cold periods. Snowmelt by radiation is thought to contribute enough meltwater during these cold periods to induce higher rates of snow glide and full-depth avalanche release. The results also indicate that snow glide alone is not a reliable indicator for full-depth avalanche release.

Amplification of seismic accelerations at slope crests

2009 ◽  
Vol 46 (5) ◽  
pp. 585-594 ◽  
Author(s):  
A. J. Brennan ◽  
S. P.G. Madabhushi
Keyword(s):  
Natural Frequency ◽  
Soil Layer ◽  
Ground Surface ◽  
Surface Structures ◽  
Centrifuge Modelling ◽  
Sloping Ground ◽  
Topographic Amplification ◽  
Tensile Forces ◽  
Seismic Accelerations

Earthquake accelerations can cause many problems in sloping ground. One such problem is that accelerations are greatly amplified at the crest of slopes. This topographic amplification can lead to acceleration gradients along the ground surface, which could create tensile forces in long surface structures that extend between areas of different amplifications. This paper uses centrifuge modelling to demonstrate and quantify this as a problem for a particular slope configuration. A special brittle structure has been constructed to undergo damage in the presence of large differential accelerations. The structure is seen to connect the crest to the level ground behind the crest during an earthquake, reducing the amplitude of the crest motion at the expense of structural tension. Topographic amplification is shown to be a clear function of frequency, and is especially serious for loading frequencies above the natural frequency of the soil layer.

Three-dimensional numerical modelling of discrete piles used to stabilize landslides

2011 ◽  
Vol 48 (9) ◽  
pp. 1393-1411 ◽  
Author(s):  
S. Kanagasabai ◽  
J. A. Smethurst ◽  
W. Powrie
Keyword(s):  
Slip Plane ◽  
Numerical Models ◽  
Three Dimensional ◽  
Ground Surface ◽  
Lateral Force ◽  
Plane Interface ◽  
Single Pile ◽  
Sloping Ground ◽  
Stabilizing Piles ◽  
Rigid Pile

Three-dimensional finite difference analyses have been carried out to investigate the behaviour of a single pile used to stabilize a slipping mass of soil by embedment into a stable stratum. Analyses were initially carried out to determine the reduction in the limiting pile–soil lateral force per metre length, pu, close to the unconfined ground surface. The analyses then explore the failure mechanisms for landslide stabilizing piles categorized by Viggiani. The effects of varying the strength of the slip plane interface between the sliding and stable strata, and of a sloping ground surface on the behaviour of the pile are then investigated. The results from numerical models with a rigid pile, a distinct plane of sliding, and a horizontal ground surface, as assumed by Viggiani, agree well with his theoretical mechanisms. Lower values of pu close to the ground surface and adjacent to the sliding plane are found to reduce the maximum shear resistance that piles can provide to the slipping mass when compared with Viggiani’s theoretical solutions. Further analyses show that the strength of the slip plane interface has a considerable influence on pile behaviour, and that the slope of the ground surface is only significant above a certain angle.

scholarly journals EXPERIMENTAL AND THEORETICAL RESEARCH OF DEFORMATION OF VERTICALLY LOADED DISPLACEMENT PILES IN SAND SOIL / SPRAUSTINIŲ POLIŲ, APKRAUTŲ VERTIKALIOSIOMIS GNIUŽDYMO APKROVOMIS, SMĖLINIO PAGRINDO NUOSĖDŽIŲ TEORINIS IR EKSPERIMENTINIS TYRIMAS

2014 ◽  
Vol 6 (5) ◽  
pp. 493-498
Author(s):  
Tautvydas Statkus ◽  
Vaidas Martinkus
Keyword(s):  
Western Europe ◽  
Ground Surface ◽  
Full Scale ◽  
Theoretical Research ◽  
Sand Soil ◽  
Glacial Origin ◽  
Local Experience ◽  
The World ◽  
Single Piles

The displacement piles are one of the oldest type of foundation not just in Lithuania, but also all over the world. Stiff, glacial origin sands lay not far from the ground surface in Lithuania as opposed to the rest of the Western Europe, therefore this kind of foundation is carried out into practice very often in our country. For geotechnical engineers it is very hard to decide which method should be applied, when there is no local experience. Five approaches are discussed on this paper and the results of three single piles’ tests are compared. The full scale single piles’ tests were carried out at the artificial bearing stratum pit. Piles’ diameter was 330 mm. The ratio of the piles’ depth and diameter were 3.3, 4.4 and 4.8. In conclusion of this paper the recommendations are given, which should be applied in different cases using mentioned above methods. Spraustiniai poliai yra vienas seniausių ir efektyviausių pamatų tipų Lietuvoje ir visame pasaulyje. Lietuvoje, skirtingai negu vakarų Europoje, stiprūs ledyninės kilmės smėliniai gruntai slūgso netoli žemės paviršiaus, dėl to mūsų šalyje dažnai įrenginėjami trumpi poliai, kurių gylis ne didesnis kaip penki polio skersmenys. Geotechnikams projektuojant tokio tipo polius sunku pasirinkti tinkamą metodą neturint vietinės patirties. Šiame straipsnyje analizuojami penki polio pagrindo nuosėdžių prognozavimo metodai, o jais apskaičiuoti nuosėdžiai lyginami su trijų statinės apkrovos polių bandymų rezultatais. Bandymai atlikti dirbtinio pagrindo duobėje, naudojant realių matmenų metalinius 330 mm skersmens polius. Poliai bandyti esant tokiems gylio ir skersmens santykiams 3,3, 4,4 ir 4,8. Straipsnio išvadose nurodomi metodai, tiksliausiai atitikę eksperi­mentų rezultatus.

FULL-SCALE LABORATORTY TESTING OF SOIL-PIPE INTERACTION IN BRANCHED POLYETHYLENE PIPELINES

2005 ◽  
Vol 29 (2) ◽  
pp. 33-37 ◽  
Author(s):  
C. Anderson ◽  
D. Wijewickreme ◽  
C. Ventura ◽  
A. Mitchell
Keyword(s):  
Full Scale ◽  
Branched Polyethylene ◽  
Soil Pipe

Analysis of buried pipelines subjected to ground surface settlement and heave

2015 ◽  
Vol 52 (8) ◽  
pp. 1058-1071 ◽  
Author(s):  
George P. Kouretzis ◽  
Dimitrios K. Karamitros ◽  
Scott W. Sloan
Keyword(s):  
Three Dimensional ◽  
Ground Surface ◽  
Ease Of Use ◽  
Surface Settlement ◽  
Buried Pipelines ◽  
Analytical Methodology ◽  
Ground Surface Settlement ◽  
Potential Alternative ◽  
Internal Forces ◽  
Pipeline Design

This paper presents an analytical methodology for the calculation of internal forces and strains developing in continuous buried pipelines that cross geotechnically problematic areas and are susceptible to permanent ground surface settlement or heave. Material nonlinearity effects are introduced in the solution via an iterative procedure, while taking into account the effect of pipeline elongation on its response. The use of a versatile bilinear expression to describe the stress–strain response of the pipeline material renders the method appropriate for steel, high-density polyethylene (HDPE), concrete, and cast iron pipelines alike. Comparison of the analytical results against those from benchmark finite element analyses highlights the effectiveness of the simplified analysis. The method is a potential alternative to elaborate three-dimensional nonlinear numerical analyses that are often used in pipeline design practice, and offers ease-of-use with no expense in accuracy, at least for problems involving simple pipeline geometries.

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