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Modelling of space weather effects on pipelines 总被引：1，自引：0，他引：1
Antti Pulkkinen Risto Pirjola David Boteler Ari Viljanen Igor Yegorov 《Journal of Applied Geophysics》2001,48(4)
The interaction between the solar wind and the Earth's magnetic field produces time varying currents in the ionosphere and magnetosphere. The currents cause variations of the geomagnetic field at the surface of the earth and induce an electric field which drives currents in oil and gas pipelines and other long conductors. Geomagnetically induced currents (GIC) interfere with electrical surveys of pipelines and possibly contribute to pipeline corrosion.In this paper, we introduce a general method which can be used to determine voltage and current profiles for buried pipelines, when the external geoelectric field and the geometry and electromagnetic properties of the pipeline are known. The method is based on the analogy between pipelines and transmission lines, which makes it possible to use the distributed source transmission line (DSTL) theory. The general equations derived for the current and voltage profiles are applied in special cases. A particular attention is paid to the Finnish natural gas pipeline network.This paper, related to a project about GIC in the Finnish pipeline, thus provides a tool for understanding space weather effects on pipelines. Combined with methods of calculating the geoelectric field during magnetic storms, the results are applicable to forecasting of geomagnetically induced currents and voltages on pipelines in the future. 相似文献
2.
3-D shell analysis of cylindrical underground structures under seismic shear (S) wave action 总被引：1，自引：1，他引：1
George P. Kouretzis George D. Bouckovalas Charis J. Gantes 《Soil Dynamics and Earthquake Engineering》2006,26(10):909-921
The 3-D shell theory is employed in order to provide a new perspective to earthquake-induced strains in long cylindrical underground structures, when soil-structure interaction can be ignored. In this way, it is possible to derive analytical expressions for the distribution along the cross-section of axial, hoop and shear strains and also proceed to their consistent superposition in order to obtain the corresponding principal and von Mises strains. The resulting analytical solutions are verified against the results of 3-D dynamic FEM analyses. Seismic design strains are consequently established after optimization of the analytical solutions against the random angles which define the direction of wave propagation relative to the longitudinal structure axis, the direction of particle motion and the location on the structure cross-section. The basic approach is demonstrated herein for harmonic shear (S) waves with plane front, propagating in a homogeneous half-space or in a two layer profile, where soft soil overlays the bedrock. 相似文献
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It is the purpose of this study to investigate the dynamic behaviour of catenary pipelines for marine applications, assuming the combined effect of harmonic motions imposed at the top, and the internal slug-flow. The analysis is based on the assumption of a steady slug-flow inside the pipe that results in a relatively simplified model for the formulation of the internal flow. The slug-flow model is described using several assumptions and empirical correlations which attempt to reveal the ill-understood and concealed properties of the slug-flow. The pipeline dynamics are investigated in the two dimensional space omitting the out-of-plane vibrations. The system of differential equations is generic and accounts for the steady effect of the internal liquid as is conveyed through the structure.The two models, those of the internal slug-flow and the pipeline’s dynamical model, are properly combined through the internal flow terms of the dynamic equilibrium system. The solution provided is achieved using a frequency domain technique which is applied to the linearized governing set. The effect of the slug-flow is assessed through comparative computations with and without internal flow effects. The conclusions are drawn having the structure excited under axial and normal motions paying particular attention to the variation of the dynamic components along the complete length of the pipeline. 相似文献
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在管道检测、探测、铺设、修复和更新等工程中,非开挖技术正在发挥着巨大的作用。通过笔者参加的2010年11月国际非开挖技术协会（ISTT）在新加坡召开的第28届年会和之前在新加坡南洋理工大学召开的第12届国际非开挖技术研讨会,从国际会议的论文中和研讨会上各国教授的介绍中提炼了非开挖工程方面的发展近况,从管道探测、检测、修复和新材料四个方面入手,简单扼要地阐述了非开挖工程的最新进展．希望对国内非开挖工程领域的研究有所帮助。 相似文献
6.
Mark F. Randolph Christophe Gaudin Susan M. Gourvenec David J. White Noel Boylan Mark J. Cassidy 《Ocean Engineering》2011,38(7):818-834
The paper presents an overview of recent developments in geotechnical analysis and design associated with oil and gas developments in deep water. Typically the seabed in deep water comprises soft, lightly overconsolidated, fine grained sediments, which must support a variety of infrastructure placed on the seabed or anchored to it. A particular challenge is often the mobility of the infrastructure either during installation or during operation, and the consequent disturbance and healing of the seabed soil, leading to changes in seabed topography and strength. Novel aspects of geotechnical engineering for offshore facilities in these conditions are reviewed, including: new equipment and techniques to characterise the seabed; yield function approaches to evaluate the capacity of shallow skirted foundations; novel anchoring systems for moored floating facilities; pipeline and steel catenary riser interaction with the seabed; and submarine slides and their impact on infrastructure. Example results from sophisticated physical and numerical modelling are presented. 相似文献
7.
Rosario Iturbe Alejandrina Castro Guillermina Perez Carlos Flores Luis G. Torres 《Environmental Geology》2008,55(8):1785-1795
For the year 1996, 366 incidents related with clandestine poaching of oil-products were reported in Mexico, 159 in 1997, and
240 in 1998. For the year 2003 (the most recently reported figure), there were 136 events. Petroleos Mexicanos (PEMEX), very
concerned with the environmental agenda, has developed programs oriented to diminish contamination levels in all of its oil
facilities. This work was aimed at characterizing zones around polyduct segments, pipelines, pumping stations, and right-of-way
pipelines located in the center of Mexico. The TPH contaminated sites were, in decreasing order, polyduct km 39 + 150 > polyduct
km 25 + 020 > Zoquital > Tepetitlan > Catalina > Venta Prieta > Ceiba. Most of the sampled points showed the presence of more than one of the 16 PAHs considered by USEPA as priority pollutants.
Except point TEPE 2A, where no PAHs were detected, all the sampled points showed values from low to medium concentrations;
however, values found at the sites did not exceed the limits according to the Mexican or the American legislation. The place
with the largest contaminated area corresponded to the polyduct km 39 + 150, with 130 m2 and 260 m3 to be treated. The least contaminated area was that around the JUAN 4 point at Juandho station, with 20 m2 and 22 m3 of contaminated soil. The total area to be treated is about 230 m2 and 497 m3. 相似文献
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It is well known that the design of submarine pipelines relies on accurate test results for the local buckling collapse of pipes subjected to bending loading. The present paper analyses apparently anomalous values of axial tensile and compressive strains from recent test results in comparison to the values that would be expected on the basis of simple bending theory. This could have important consequences for the efficacy of the design factors derived using these results. The cause of the differences between the strain values obtained in the tests and those expected on the basis of simple bending theory are explained using finite element modelling. The differences result from the type of collars and supports commonly used in bending tests, the effects of which persist for a greater length along the test pipe than has hitherto been assumed. In general, it is pointed out that the application of the simplified engineering theory of bending can be erroneous when ovalisation is imposed or, on the contrary, the boundary conditions of the section are restrained from ovalising deformations. The influence of the D/t ratio is also analysed.The results contribute to the understanding of a crucial limit state for the design of onshore and offshore pipelines. 相似文献
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At the present time, it is very common in practice to utilize Mohr-Coulomb model to simulate the soil behaviour in the application of soil-pipeline interaction problems. However, the traditional Mohr-Coulomb model is unable to predict the realistic loading that can apply on buried pipes during large ground deformation. Especially, the linear elastic-perfectly plastic Mohr-Coulomb model is not capable of simulating the unsaturated soil loading which can result larger than anticipated loading due to suction induced additional normal force between the soil particles. A user defined unsaturated modified Mohr-Coulomb model is developed within a generalized effective stress framework considering suction hardening effects to capture the realistic loading induced by unsaturated soil medium. Firstly, the model has been developed considering microscopic and macroscopic suction hardening mechanisms, and was implemented into a commercial finite element program associated with user subroutine written in FORTAN. Then the model was validated through a series of unsaturated triaxial compression tests conducted on the basis of different sand types having various initial conditions. Finally, the model has been applied to simulate the behaviour of pipelines subjected to lateral soil loading in unsaturated soils. The results revealed that the modified Mohr-Coulomb model has reasonable predictions when compared to the load-displacement response of pipes obtained from two large scale testing programs. The developed model can be used to predict the increased strength and stiffness associated with soil suction that increases lateral loads on pipelines, and thus has widespread relevance for simulating the pipeline response in unsaturated soils under externally imposed ground movement. 相似文献