• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2006년도 학술발표회 논문집
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• pp.358-365
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• 2006

In this study, fragility curves of continuous buried pipelines subjected to transverse PGD (permanent ground deformation) due to liquefaction are proposed. For the waterworks system, continuos buried pipelines made of ductile iron, poly ethylene, and poly vinyl chloride are analyzed and fragility curves are drawn. Fragility curves are based on the repetitive analyses results and formulated with the dominant factors of behaviour of buried pipeline. With the use of fragility curves, engineers can estimate the status of damage of buried pipeline without overall knowledge of relevant features. Especially, fragility curves proposed in this study will act as a major module of earthquake loss estimation method. Moreover, critical value of magnitude and width of transverse PGD (by which the full damage status of buried pipelines are induced) are estimated. With the use of regression curves of these values, pre evaluation of seismic safety of buried pipelines located within liquefaction hazardous region will be possible.

• 한국농공학회지
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• 제41권6호
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• pp.64-74
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• 1999

The frequency of earthquake occurrence tends to increase in Korea. Therefore, the stability of pipeline, such as watersupply pipe, gas pipe, and oil pipe etc. across fault zones in Gyoung-sang landmass is very important, expecially , in metropolitan area. There were some examples of the construction of buried pipeline across fault zones in Korea. the interactiion between the buried pipeline across fault zones and the ground is considered. As well, in the interfaces of them, the direct shear numerical analysis model including elasto-plastic joint element is assumed that the retained dilatancy theory in them, otherwise. Also, the other elements are modeled the ground is nonlinear elastic coutinuaus beam, respectively. In this study, the maximum shear force point exist inside retaine zone(anchored zone) during shwar (as fault sliding), and the distribution of pipeline's behavior is all alike them of pipeline buried in ladnsliding grounds. Since the pipeline is not continuous beam but jointed by steel-pipe segments , practically, on acting of a large bending moment or a shear force, then, those are may be unstable. The reaearch on this point may be new approach.

• Geomechanics and Engineering
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• 제37권2호
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• pp.189-195
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• 2024

Buried pipelines can be classified as continuous and segmented pipelines. These infrastructures can be damaged either by ground movement or by seismic wave propagation during an earthquake. Permanent ground deformations (PGD) include surface faulting, liquefaction-induced lateral spreading and landslide. Liquefaction is a major problem for both superstructures and infrastructures. Buyukcekmece lake zone, which is the studied region in this paper, is a liquefaction prone area located near the North Anatolian Fault Line. It is an active fault line in Turkey and a major earthquake with a magnitude of around 7.5 is expected in this investigated region in Istanbul. It is planned to be constructed a new 12" steel natural gas pipeline from one side of the lake to the other side. In this study, this case has been examined in terms of two different support conditions. Firstly, it has been defined as a beam in liquefied soil and has built-in supports at both ends. In the other approach, this case has been modeled as a beam in liquefied soil and has vertical elastic pinned supports at both ends. These models have been examined and some solution proposals have been produced according to the obtained results. In this study, based on this sample, it is aimed to determine the behaviors of buried continuous pipelines subject to liquefaction effects in terms of buoyancy.

• Geomechanics and Engineering
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• 제34권4호
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• pp.409-424
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• 2023

Response of the pipeline crossing fault is considered as the large strain problem. Proper estimation of the pipeline response plays important role in mitigation studies. In this study, an advanced continuum modeling including material non-linearity in large strain deformations, hardening/softening soil behavior and soil-pipeline interaction is applied. Through the application of a fully nonlinear analysis based on an explicit finite difference method, the mechanics of the pipeline behavior and its interaction with soil under large strains is presented in more detail. To make the results useful in oil and gas engineering works, a continuous pipeline of two steel grades buried in two clayey soil types with four different crossing angles of 30°, 45°, 70° and 90° with respect to the pipeline axis have been considered. The results are presented as the fault movement corresponding to different damage limit states. It was seen that the maximum affected pipeline length is about 20 meters for the studied conditions. Also, the affected length around the fault cutting plane is asymmetric with about 35% and 65% at the fault moving and stationary block, respectively. Local buckling is the dominant damage state for greater crossing angle of 90° with the fault displacement varying from 0.4 m to 0.55 m. While the tensile strain limit is the main damage state at the crossing angles of 70° and 45°, the cross-sectional flattening limit becomes the main damage state at the smaller 30° crossing angles. Compared to the stiff clayey soil, the fault movement resulting 3% tensile strain limit reach up to 40% in soft clayey soil. Also, it was seen that the effect of the pipeline internal pressure reaches up to about 40% compared to non-pressurized condition for some cases.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 A
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• pp.130-132
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• 2002

Because of the continuous growth of energy consumption and also the tendency to site power lines and pipelines along the same route, the close proximity of power lines and buried metallic pipelines has become more and more frequent. Therefore there has been and still is a slowing concern about possible hazards resulting from the influence of power lines on metallic pipelines. Underground pipelines that run parallel to or in close proximity to power lines are subjected to induced voltages caused by the time-varying magnetic fields produced by the power line currents. The induced electro- motive force cause currents circulation in the pipeline and voltages between the pipeline and surrounding earth. This paper analyzes the induced voltage on the gas pipelines buried in parallel with 22.9kV distribution lines. Their magnitude depends on the length of parallelism and on the distance between distribution lines and pipeline.

• 한국지진공학회논문집
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• 제6권2호
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• pp.51-61
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• 2002

본 연구에서는 액상화-종방향 영구지반변형에 대한 지중매설관로의 거동특성을 해석하기 위하여 수치해석 알고리즘을 개발하였다. 기존의 연구결과가 간략한 해석식의 제안을 중심으로 진행되어 왔으며 영구지반변형의 형상과 폭에 따라 해석방법이 달라지는 단점을 가지고 있었던 것을 고려한다면, 개발된 수치해석 기법은 다양한 영구지반변형의 형상과 폭을 단일한 알고리즘 내에서 처리할 수 있다는 특징을 가지고 있다. 이를 위해 본 연구에서는 연속관 형태의 지중매설관로와 주변지반을 보요소와 등가지반강성으로 표현되는 탄-소성 지반 스프링을 이용하여 모형화하였으며, 지진발생시 실측된 지반변형에 기초하여 영구지반변형의 형상을 5가지의 대표적인 형태로 이상화하여 고려하였다. 국내 계기지진피해사례의 부족으로 인하여 영구지반변형의 크기와 지반변형의 폭은 기존의 연구결과를 참조하여 설정하였으며, 국내에서 사용되는 일반적인 강관을 대상으로 지반변형의 형상과 크기 및 폭, 매설관로의 관경, 관두께 등을 변화시켜 가면서 다양한 수치해석을 수행하였다. 수치해석 결과, 종방향 영구지반변형에 대한 매설관로의 거동에 미치는 주요 인자들의 영향정도를 평가할 수 있었다.

• 전기학회논문지
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• 제57권10호
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• pp.1720-1725
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• 2008

Because of the continuous increasing of energy consumption, metallic pipelines are widely used to supply services to customers such as gas, oil, water, etc. Most common metallic pipelines are underground and are now frequently being installed in nearby electric power lines. In recent years, buried gas pipeline close to power lines can be subjected to hazardous induction effects, especially during single line to ground faults. because it can cause corrosion and it poses a threat to the safety of workers responsible for maintenance. Accordingly, it is necessary to take into consideration for analysis of induced voltage on gas pipelines in transmission lines. This paper analyzed the induced voltage on the gas pipelines due to the 154kV transmission lines in normal case and in different faulty case conditions using EMTP (Electro-Magnetic Transients Program).

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 A
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• pp.470-473
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• 2000

Because of the continuous growth of energy consumption, and also the tendency to site power lines and pipelines along the same routes, the close proximity of high voltage structures and metallic pipelines has become more and more frequent. Moreover, normal steady state and fault currents become higher as electric networks increase in size and power. Therefore, there has been and still is a growing concern (safety of people marking contact with pipeline, risk of damage to the pipeline coating, the metal and equipment connected to pipeline. especially cathodic protection system) about possible hazards resulting from the influence of high voltage power system on metallic structures(gas pipeline, oil pipeline and water pipeline etc.). Therefore, we analyze the interference problems when the gas pipeline is buried with power cable in the same submarine tunnel. This paper present the results of the study about interference mechanism, AC corrosion, limitation of safety voltage and analysis of indiction voltage.

• 대한토목학회논문집
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• 제37권1호
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• pp.175-185
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• 2017

가스 사용의 지속적인 증대로 이에 따른 가스의 제조, 취급, 사용이 점점 확대되어 관련 시설이 대형화, 복잡화되어, 이로 인한 크고 작은 사고가 지속적으로 발생하고 있다. 이러한 사고는 인명피해 및 물적 손실 뿐만 아니라 국가의 경제적인 손실의 큰 원인이 된다. 가스시설의 공통적으로 많은 부분을 차지하고 있는 Pipe Line 부분에 외부의 영향에 의한 사고가 가장 큰 위험요소를 가지고 있다. 특히, 도심지역 및 인구밀집지역의 경우의 고압가스배관의 사고 발생은 경제적 손실을 비롯한 보다 많은 손실을 야기시킬 수 있다. 이러한 매설배관의 사고에 대한 예방대책으로 여러 관련 기관에서는 가스배관에 대한 안전성을 확보하기 위해서는 전체 시스템의 파손 및 위험요소를 효과적으로 평가할 필요가 있다. 특히 가스배관이 설치되거나 작동되어 질 때에 이러한 파손(failure)의 가능성을 매우 작게 하더라도 위험요소가 존재하게 된다. 그러나 일단 파손이 발생하면 인명 및 재산상의 피해가 매우 크기 때문에 파손의 원인을 분석하여 파손사고의 비율을 최소한으로 낮추는 것이 필요하다. 그러므로 본 논문에서는 Scoring Model의 정성적 위험성 분석기법을 이용하여 매설배관의 위험성을 점수로 표현하여 정량적인 숫자로 표현하였다. 이러한 가시적인 평가의 결과는 매설배관의 안전을 확보하여 실질적인 매설배관의 유지관리를 하는데 있어서 매우 효율적으로 적용될 수 있을 것이다.

• Earthquakes and Structures
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• 제1권3호
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• pp.253-267
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• 2010

A novel simple approach is presented for the seismic analysis of continuous buried pipelines subject to fault ruptures. The method is based on the minimization of the total dissipated energy during faulting, taking into account the basic factors that affect the problem, namely: a) the pipe yielding under axial and bending load, through the formation of plastic hinges and axial slip; b) the longitudinal friction across the pipe-soil interface; c) the lateral resistance of soil. The advantages and drawbacks of the proposed method are highlighted through a comparison with previous approaches, as well as with finite element calculations accounting for the 3D kinematics of the pipe-soil-fault systems under large deformations. Parametric analyses are also provided to assess the relative influence of the various parameters affecting the problem.