Soil-Pipe Interaction and Pipeline Design

1981 ◽  
Vol 107 (1) ◽  
pp. 45-58
Author(s):  
Syed Ahmed ◽  
Carl L. Brassow ◽  
Ralph W. McMickle
Keyword(s):  
Author(s):  
Gregory C. Sarvanis ◽  
Spyros A. Karamanos ◽  
Polynikis Vazouras ◽  
Panos Dakoulas ◽  
Elisabetta Mecozzi ◽  
...  

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.


Author(s):  
Euro Casanova ◽  
Armando Blanco

Offshore production fields require long submarine pipelines for transporting production fluids that are inherently multiphase. This condition and hydraulic sizing of pipelines lead often to the development of slug flow patterns in which condensate slugs traveling in the pipeline, act as moving gravity loads for the piping structure, therefore producing a dynamic response especially important for the free spans. Recently some authors have shown that this phenomenon may produce a cyclic damage that could reduce in a significant way the fatigue life of the pipelines, thus constituting a governing mechanism in their design. On the other hand, pipe-soil interaction has also been identified as an important factor in pipeline design and fatigue life; in particular it is important for determination of the static equilibrium configurations and the vibration response of free spanning pipelines. In this work a previously presented numerical model which combines fluid equations for predicting slug characteristics and a structural finite element model for the pipelines transporting slugs, is improved by introducing non linear characteristics of seabed supports. Different seabed supports (linear, perfectly plastic, and non linear with tension cut-off) and different properties of soil-pipe interaction (stiffness, damping and length of soil-pipe interaction) are considered, and their effects on vibration response and fatigue life are compared. Results show that soil pipe interaction is an important parameter in vibration response and fatigue life for pipeline spans subjected to slug flow.


Author(s):  
Abdelfettah Fredj ◽  
Aaron Dinovitzer ◽  
Joe Zhou

Soil-pipe interactions when large ground movements occur are an important consideration in pipeline design, route selection, guide monitoring and reduce the risk of damage or failure. Large ground movement can be caused by slope failures, faulting, landslides and seismic activities. Such conditions induce large deformations of both the soil and pipe. Analyses of such behavior pose a significant challenge to capabilities of standard finite elements as the capability to analyze large deformations is required. This requirement is difficult to meet for Lagrangian-based code. New developments using ALE methods make it possible to determine soil and pipe deformation confidently for large displacements. This paper describes a study performed to investigate the mechanical behavior of a pipeline subjected to large soil movement. A 3D continuum modeling using an ALE (Arbitrary Eulerian Lagrangian) formulation was developed and run using LS-DYNA. The results are compared with published experimental data of large-scale test to verify the numerical analysis method. The analysis is further extended to analyze the soil-pipe interaction under permanent ground deformation such as those associated with surface fault rupture and landslides.


1982 ◽  
Vol 108 (2) ◽  
pp. 221-226
Author(s):  
J.M.E. Audibert ◽  
Kenneth J. Nyman
Keyword(s):  

Author(s):  
V. A. Martynyuk ◽  
V. A. Trudonoshin ◽  
V. G. Fedoruk

The article considers applications of foreign CAD-systems in creating the challenging projects at domestic enterprises and design bureaus. As stated in the article "... presently, there is no domestic CAD-system that could completely replace such foreign products as NX, CATIA, Credo". Besides, due to international cooperation in creating the challenging projects (for example, the project to create a modern wide-body aircraft, proposed jointly with China), it makes sense to use the worldwide known and popular CAD systems (the aforementioned NX, CATIA, Credo). Therefore, in the foreseeable future, we will still have to use foreign software products. Of course, there always remains a question of the reliability of the results obtained. Actually, this question is always open regardless of what software product is used - domestic or foreign. This question has been haunting both developers and users of CAD systems for the last 30 to 40 years. But with using domestic systems, it is much easier to identify the cause of inaccurate results and correct the mathematical models used, the methods of numerical integration applied, and the solution of systems of nonlinear algebraic systems. Everything is much more complicated if we use a foreign software product. All advertising conversations that there is a tool to make the detected errors available to the developers, remain only conversations in the real world. It is easily understandable to domestic users, and, especially, to domestic developers of similar software products. The existing development rates and competition for potential buyers dictate a rigid framework of deadlines for releasing all new versions of the product and introducing the latest developments into commercial product, etc. As a result, the known errors migrate from version to version, and many users have accepted it long ago. Especially, this concerns the less popular tools rather than the most popular applications (modules) of a CAD system. For example, in CAD systems, the "Modeling" module where geometric models of designed parts and assembly units are created has been repeatedly crosschecked. But most of the errors are hidden in applications related to the design of parts from sheet material and to the pipeline design, as well as in applications related to the analysis of moving mechanisms and to the strength or gas dynamic analysis by the finite element method.The article gives a concrete example of a moving mechanism in the analysis of which an error was detected using the mathematical model of external influence (a source of speed) in the NX 10.0 system of Siemens.


Author(s):  
Sandip K Lahiri ◽  
Kartik Chandra Ghanta

Four distinct regimes were found existent (namely sliding bed, saltation, heterogeneous suspension and homogeneous suspension) in slurry flow in pipeline depending upon the average velocity of flow. In the literature, few numbers of correlations has been proposed for identification of these regimes in slurry pipelines. Regime identification is important for slurry pipeline design as they are the prerequisite to apply different pressure drop correlation in different regime. However, available correlations fail to predict the regime over a wide range of conditions. Based on a databank of around 800 measurements collected from the open literature, a method has been proposed to identify the regime using artificial neural network (ANN) modeling. The method incorporates hybrid artificial neural network and genetic algorithm technique (ANN-GA) for efficient tuning of ANN meta parameters. Statistical analysis showed that the proposed method has an average misclassification error of 0.03%. A comparison with selected correlations in the literature showed that the developed ANN-GA method noticeably improved prediction of regime over a wide range of operating conditions, physical properties, and pipe diameters.


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