Simulation of the Response of Buried Pipelines to Slope Movement Using 3D Continuum Modeling

2012 ◽  
Author(s):  
Abdelfettah Fredj ◽  
Aaron Dinovitzer
Keyword(s):  
Fluid Pressure ◽  
Slope Movement ◽  
Ground Movement ◽  
Ground Subsidence ◽  
Continuum Modeling ◽  
Buried Pipelines ◽  
Design Standards ◽  
Codes Of Practice ◽  
Modeling Process ◽  
Ongoing Work

Pipeline integrity is affected by the action of external soil loads in addition to internal fluid pressure. External soil loads can be generated by landslides or at sites subject to ground subsidence, heave or seismic effects. Under these varied conditions of ground movement potential pipeline safety involves constraints on design and operations. The design processes includes developing an understanding of strains that could be imposed on the pipe (strain demand) and strain limits that the pipe can withstand without failure. The ability to predict the pipeline load, stress or strains state in the presence of soil restraint and/or soil displacement induced loading is not well described in design standards or codes of practice. This paper describes the ongoing work involved in a study investigating the mechanical behavior of buried pipelines interacting with active landslides. Detailed pipe-soil interaction analyses were completed with a 3D continuum SPH method. This paper describes the LS-DYNA numerical modeling process, previously developed by the authors, which was refined and applied to site-specific conditions. To illustrate the performance of the modeling process to consider a translational slide, additional numerical model validation was completed and is described in this paper. These comparisons illustrate that good agreement was observed between the modeling results and experimental full scale trial results. Sample results of the application of the validated 3D continuum modeling process are presented. These results are being used to develop generalized trends in pipeline response to slope movements. The paper describes both the progress achieved to date and the future potential for simplified engineering design tools to assess the load or deformation capacity requirements of buried pipelines exposed to different types of slope movement.

Pipeline Response to Slope Movement and Evaluation of Pipeline Strain Demand

2014 ◽  
Author(s):  
Abdelfettah Fredj ◽  
Aaron Dinovitzer
Keyword(s):  
Slope Failure ◽  
Smooth Particle Hydrodynamic ◽  
Slope Movement ◽  
Soil Conditions ◽  
Burial Depth ◽  
Design Standards ◽  
Element Analysis ◽  
Modeling Tools ◽  
Soil Movement ◽  
Codes Of Practice

Pipelines installed on active slopes can be exposed to slope failure mechanisms. The soil movement can introduce substantial axial and bending strains on buried pipeline, and possibly damage. The techniques to predict pipeline displacements, loads, stress or strains are not well described in design standards or codes of practice. The practice of using finite element analysis of soil-pipe interaction has developed in recent years and is proving to be a useful tool in evaluating the pipeline behavior in response to slope movement. A description of advanced pipe soil interaction modeling tools and their validation against full scale trails has been previously presented. This paper describes the ongoing work involved in a study investigating the mechanical behavior of buried pipelines interacting with active slope movement and evaluation of pipeline strain demand. Detailed pipe-soil interaction analyses were completed with a 3D continuum SPH (Smooth Particle Hydrodynamic) model to examine the pipeline behavior and evaluate the pipeline strain demand in relation to key parameters. This includes the effect of soil movement mechanism, pipeline geometry (D/t), material grade, pipeline burial depth and soil conditions and properties. Sample results of the application of the validated 3D continuum modeling process will be presented. The strain demand determined from the analyses were compared with calculated CSA-Z662 strain limit design, local FEA analyses and BS 7910. These results are being used to develop generalized trends in pipeline response to slope movements.

The Contribution of In-Line IMU Inspection to Geohazard and Crack Management Strategies

2021 ◽  
Author(s):  
Andy Young ◽  
Andrew Wilde ◽  
Ivan Grosmann
Keyword(s):  
Management Practices ◽  
Load Capacity ◽  
Management Strategies ◽  
High Strength ◽  
Ground Movement ◽  
Ground Subsidence ◽  
Measurement Unit ◽  
External Loading ◽  
Integrity Management ◽  
The Right

Abstract Geohazards and external loads are a significant threat to the integrity of pipelines in hilly terrain, at river crossings and where ground subsidence is taking place. Well designed pipelines can tolerate strains that exceed the nominal strain of 0.5% that corresponds specified minimum yield strengths, however the presence of weld defects and stress corrosion cracking can reduce the load capacity dramatically. Welds that are to specification but are under-matched on actual strength to the adjacent parent pipe have also been recognised as potentially vulnerable to low strain failures in high strength pipes. Modern pipelines in terrain susceptible to geohazards normally include design studies to identify and avoid or mitigate the threats. Surveillance of the right-of-way is also routinely carried out for pipelines with good integrity management practices, and particularly for major strategic lines. In-line inspection using an inertial measurement unit (IMU) is a well-known method to detect ground movement loads and contributes to the integrity management of pipelines. In this paper we illustrate : 1. How IMU inspection is an important tool in the management of geohazards and how it compliments other methods of geohazard assessment. 2. How locations of elevated pipe strain are identified and evaluated for external loading threats, and can be aligned with other data sets that indicate the pipeline load capacity. 3. How the locations of bending strain can be prioritised for further action. 4. How the loading profile in the pipeline can be incorporated into crack management strategies in order prioritise locations for further investigation or assessment.

Serviceability Assessment of Composite Footbridge Under Human Walking and Running Loads

2015 ◽  
Vol 74 (4) ◽  
Author(s):  
Faraz Sadeghi ◽  
Ahmad Beng Hong Kueh
Keyword(s):  
Concrete Slab ◽  
Model Verification ◽  
Human Walking ◽  
Steel Beams ◽  
Vibration Source ◽  
Design Standards ◽  
Reinforced Concrete Slab ◽  
Codes Of Practice ◽  
Current Design ◽  
Vibration Responses

Footbridge responses under loads induced by human remain amongst the least explored matters, due to various uncertainties in determining the description of the imposed loadings. To address this gap, serviceability of an existing composite footbridge under human walking and running loadings is analyzed dynamically in this paper employing a finite element approach. The composite footbridge is made-up of a reinforced concrete slab simply supported at two ends on top of two T-section steel beams. To model the walking and running loads, a harmonic force function is applied as the vibration source at the center of the bridge. In the model verification, the computed natural frequency of footbridge exhibits a good agreement with that reported in literature. The vibration responses in terms of peak acceleration and displacement are computed, from which they are then compared with the current design standards for assessment. It is found that the maximum accelerations and displacements of composite footbridge in presence of excitations from one person walking and running satisfy the serviceability limitation recommended by the existing codes of practice. In conclusion, the studied footbridge offers sufficient human safety and comfort against vibration under investigated load prescription.

Vulnerability of Buried Pipelines to Landslides

2016 ◽  
Author(s):  
Gerald Ferris ◽  
Sarah Newton ◽  
Michael Porter
Keyword(s):  
Ground Movement ◽  
Buried Pipelines ◽  
Large Numbers ◽  
Vulnerability Model ◽  
Cause Of Failure ◽  
Integrity Management ◽  
Pipeline Failure ◽  
As Stress ◽  
Pipeline Failures ◽  
Landslide Movement

The movement of a mass of rock, debris or earth down a slope is a landslide, which in the pipeline industry is often referred to as ground movement. Landslides continue to cause pipeline failures throughout the industry, sometimes as the singular cause of failure and in others cases as a contributing factor to failures (such as stress corrosion cracking on slopes). Landslides can originate on slopes above a pipeline and cause impact loads; they can originate below a pipeline and cause unintended spans; and they can encompass the ground crossed by a pipeline, which can lead to high compressive (or tensile) strains and pipeline buckling. This paper focuses on the latter scenario. Similar to the approach recently outlined for watercourses [1], the term ‘vulnerability’ refers to the conditional probability of pipeline failure given that landslide movement spatially impacts a pipeline. This paper presents the development of a statistical and judgment-based vulnerability model for pipeline crossings of slopes that are subject to landslides that can be used to rank the relative importance of slopes at a screening level of assessment. The model is based on case histories where this type of landslide scenario caused pipeline failures (defined as holes, leaks and ruptures), or buckling of pipelines that resulted in the need for immediate repairs. Vulnerability has two main uses: on its own to help prioritize large numbers of slope crossings for further investigation; and, once combined with estimates of the probability of landslide movement, to provide a probability of pipeline failure estimate that can be used to guide integrity management programs.

scholarly journals Additional Stress on a Buried Pipeline under the Influence of Coal Mining Subsidence

2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Ping Xu ◽  
Minxia Zhang ◽  
Zhibin Lin ◽  
Zhengzheng Cao ◽  
Xu Chang
Keyword(s):  
Coal Mining ◽  
Surface Deformation ◽  
Analytical Calculation ◽  
Mining Subsidence ◽  
Ground Subsidence ◽  
Additional Stress ◽  
Buried Pipeline ◽  
Buried Pipelines ◽  
Probability Integral Method ◽  
Coal Mining Subsidence

Buried pipelines influenced by coal mining subsidence will deform and generate additional stress during surface deformation. On the basis of the coordinating deformation relationship between buried pipeline and its surrounding soils, a stress analysis method of a buried pipeline induced by mining was proposed. The buried pipeline additional stresses were analyzed; meanwhile, a corresponding analysis process of the pipeline stresses was also presented during mining subsidence. Furthermore, based on the ground subsidence along the pipeline predicted in advance by the probability integral method, the additional stresses and Von Mises equivalent stresses and their distributions along the buried pipeline induced by the exploitation of a coal mining working face named 14101 were obtained. Meanwhile, a comparative analysis of additional stresses between simulation and analytical calculation was performed for the deep analysis and reliability of the results presented by the proposed methodology in this paper. The proposed method provides references for analysis of the additional stress and safety of buried pipelines under the influence of mining subsidence.

Influence of Geotechnical Loads on Local Buckling Behavior of Buried Pipelines

2008 ◽  
Author(s):  
Hiva Mahdavi ◽  
Shawn Kenny ◽  
Ryan Phillips ◽  
Radu Popescu
Keyword(s):  
Large Scale ◽  
Mechanical Performance ◽  
Load Capacity ◽  
Local Buckling ◽  
Small Diameter ◽  
Ground Movement ◽  
Combined Loading ◽  
Fe Model ◽  
Buried Pipelines ◽  
Limit States

Buried pipelines can be subjected to differential ground movement events. The ground displacement field imposes geotechnical loads on the buried pipeline and may initiate pipeline deformation mechanisms that exceed design acceptance criteria with respect to serviceability requirements or ultimate limit states. The conventional engineering approach to define the mechanical performance of pipelines has been based on combined loading events for “in-air” conditions. This methodology is assumed to be overly conservative and ignores soil effects that imposes geotechnical loads and also provides restraint, on buried pipelines. The importance of pipeline/soil interaction and load transfer mechanisms that may affect local buckling of buried pipelines is not well understood. In this study a three-dimensional continuum finite element (FE) model, using the software package ABAQUS/Standard, was developed and calibrated based on large-scale tests on the local buckling of linepipe segments for in-air and buried conditions. The effects of geotechnical boundary conditions on pipeline deformation mechanism and load carrying capacity were examined for a single small diameter pipeline with average diameter to thickness ratio and deep buried condition. The calibrated model successfully reproduced the large-scale buried test results in terms of the local buckling location, pipeline carrying load capacity, soil deformation and soil failure mechanism.

Satellite-Based Monitoring of Subsidence Ground Movement Impacting Pipeline Integrity

2002 ◽  
Author(s):  
James Youden ◽  
Desmond Power ◽  
Ping Han ◽  
Jerry English ◽  
Rick Gailing ◽  
...  
Keyword(s):  
Management Program ◽  
Ground Movement ◽  
Ground Subsidence ◽  
Ground Movements ◽  
Gps Survey ◽  
Management Technology ◽  
Integrity Management ◽  
Survey Results ◽  
Sar Data ◽  
Technology Institute

Ground movements due to a range of governing mechanisms are recognized to pose hazards to the operating integrity of pipelines in California. As part of an extensive technology management program, Southern California Gas Company (SoCalGas) is involved in the development and implementation of satellite-based monitoring of subsidence ground movements impacting pipeline integrity. By both hosting a Gas Technology Institute (GTI) and Pipeline Research Council International (PRCI) study and undertaking an internal study, SoCalGas is supporting the investigation of two aspects of this promising pipeline integrity management technology. The current project of monitoring ground subsidence due to oil production in the San Joaquin Valley utilizes synthetic aperture radar (SAR) to derive sub-centimeter ground movement measurements from February to September, 2001. The estimates of the subsidence derived from the SAR data are compared with GPS survey results taken at 65 monuments. In addition, archived SAR data from 1992 to 2000 are used to better estimate the movement that has occurred there over the past decade.

Random Field Modeling of Rainfall-Induced Soil Movement

2002 ◽  
Author(s):  
I. Konuk ◽  
U. O. Akpan ◽  
D. P. Brennan
Keyword(s):  
Random Field ◽  
Structural Integrity ◽  
Oil And Gas ◽  
Route Planning ◽  
Software Tool ◽  
Slope Movement ◽  
Ground Movement ◽  
Spatial And Temporal Variability ◽  
Temporal Correlations ◽  
Field Modeling

Natural oil and gas transmission pipeline networks often traverse regions where potential slow ground movements may affect pipeline structural integrity. One of the primary causes of slow ground movement in any region involves the duration, amount, and intensity of rainfall. The phenomenon of rainfall-induced slow ground movement is characterized by both spatial and temporal variability, and involves uncertainties that are best modeled using a probabilistic methodology. A random field modeling strategy is formulated in this study, in which spatial and temporal correlations between rainfall and ground movement are accounted for. The random field formulation advanced in the current study has a number of significant features and capabilities, including modeling the spatial and temporal relationship between rainfall and slope movement for specified pipeline routes, predicting the likelihood of exceeding slope movement thresholds for various precipitation levels and intensities, and providing maps of risk for slope movement, which can be used as a guide in pipeline route planning, selection, and adaptation strategies for the design and maintenance of oil and gas infrastructure. These capabilities have been implemented and encapsulated into the software tool VSLOPE, which has been tested using monthly rainfall and field data for various locations.

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