• Structural Engineering and Mechanics
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• 제47권2호
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• pp.167-183
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• 2013

Methods for estimating structural reliability using probability ideas are well established. When the residual ultimate strength of a buried pipeline is exceeded the limit, breakage becomes imminent and the overall reliability of the pipe distribution network is reduced. This paper is concerned with estimating structural failure of underground flexible pipes due to corrosion induced excessive deflection, buckling, wall thrust and bending stress subject to externally applied loading. With changes of pipe wall thickness due to corrosion, the moment of inertia and the cross-sectional area of pipe wall are directly changed with time. Consequently, the chance of survival or the reliability of the pipe material is decreased over time. One numerical example has been presented for a buried steel pipe to predict the probability of failure using Hasofer-Lind and Rackwitz-Fiessler algorithm and Monte Carlo simulation. Then the parametric study and sensitivity analysis have been conducted on the reliability of pipeline with different influencing factors, e.g. pipe thickness, diameter, backfill height etc.

• Proceedings of the Korean Geotechical Society Conference
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• 한국지반공학회 1996년도 가을 학술발표회 논문집
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• pp.25-38
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• 1996

• Proceedings of the Korea Concrete Institute Conference
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• 한국콘크리트학회 2000년도 봄 학술발표회 논문집
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• pp.880-887
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• 2000

• Journal of computational fluids engineering
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• 제10권1호
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• pp.94-98
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• 2005

Accurate prediction of the fire-induced air velocity, temperature and smoke flow in underground utility tunnel becomes more important for the optimization of design and placement of heat and smoke detectors. In order to improve the safety of underground utility tunnel systems, the behaviors of fire-induced smoke flow and temperature distributions are investigated. Especially, two different cross-sectional shapes of tunnel, such as rectangular and circular types are modeled. Also, fire source is modeled as a volumetric heat source. Three-dimensional thermal-flow characteristics in an underground tunnel are solved by means of FVM using SIMPLE algorithm. The effects of shape geometry on the fire-induced flow characteristics are graphically depicted. It is desirable that heat and smoke detectors are installed on the cables and the top of the wall.

• Proceedings of the KIEE Conference
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• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
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• pp.346-348
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• 2007

Underground pipe is an instrument to transport rapidly and safely a lot of fluid like gas, oil, water supply and drain system. It acts like blood vessels of human body in a modern industry. As in this country, the pipe facilities have been constructing since 1970's. The pipes constructed for a long time ago are already starting to reveal the problem like corrosion and most of them are built underground. So for companies, the managing of the underground pipes is very hard because it needs high technology and a lot of money. So we made a new robot system to repair and maintain the pipes at a low price. This new robot is devised using pressing wall type to work inside 700${\sim}$900(mm) size pipe. And it has good carrying and working power.

• Journal of the Korean Society of Industry Convergence
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• 제8권3호
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• pp.161-168
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• 2005

This study is analysis for adjacent structures and ground movement by deep excavation work. Underground Inclinometer has shown that deformation of increment is minor within to allowable limit. According to the measurements result of slope and crack for adjacent structures, a detached house showed bigger than hospital structure to deformation of increment. Variation of underground water level didn't effect so much to ground and adjacent structures movement because underground water flows in rock and didn't give the water press to propped walls. Measurement data of strut variation is within tolerance limit. Because excavation site's wall was strengthened suitably. This study will contribute in establishment of measurement standard and information-oriented construction during deep excavation in multi-layered ground including rock masses.

• Proceedings of the KIEE Conference
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• 대한전기학회 2001년도 추계학술대회 논문집 전력기술부문
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• pp.344-346
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• 2001

The sharing of common corridors by electric power transmission lines and pipelines is becoming more common place. However, such corridor sharing can result in undesired coupling of electromagnetic energy from the power lines to the near facilities. During a fault on any of the transmission lines, energization of the earth by supporting structures near the fault can result in large voltages appearing locally between the earth and the steel wall of any nearby pipeline. This paper presents the outline of the tower footings for the transmission lines having been used in KEPCO and analyzes the earth resistance for operation method of the tower footing, that is contact presence for the anchor and reinforcing rob of the tower and foundation presence of the underground wiring.

• Proceedings of the KIEE Conference
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 전기설비
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• pp.87-88
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• 2006

There are a number of reported instances of actual pipeline rupture during power line faults caused by melting of the pipe wall. This type of hazard was considered to be among the most serious of AC effects on pipelines in an international survey, comparable to the personnel safety hazard. Moreover, resistance coupling is not only a risk when the pipeline parallels a power line but also when they cross. One method of minimizing the effects of resistive coupling is by maintaining an appropriate separation distance between the pipeline and tower. This paper investigate the experiment for separation distance between the powerline earth and pipelines.

• Proceedings of the Korea Concrete Institute Conference
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• 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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• pp.935-938
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• 2001

This paper reports the relation of concrete setting characteristic and lateral pressure in mass concrete wall such as side wall of LNG underground storage tank. In order to estimate the lateral pressure, initial setting time of low heat cement concrete with type of mineral admixture was measured for three concrete mixtures(W/P=41.6%) containing limestone powder, fly ash, and slag powder. As a result, the lateral pressure of the concrete containing limestone powder was the smallest than those of other concretes as well as the initial setting time.

• KIEAE Journal
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• 제8권2호
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• pp.87-92
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• 2008

Underground building constructions are recently more important because the ratio of underground area is increasing in the huge and high-rise building construction projects. For reducing the total building construction periods, it is required to reduce not only the over-ground structural work periods but also the underground structural work periods. Therefore, this study is proposed the non-supporting system forms for single face walls in underground building construction by one of the methods for reducing the underground structural work periods and investigated the applicability of the non-supporting system forms by analyzing the case-study in civil construction project. In regard of construction duration, the results of analyzing the case-study showed that the non-supporting system forms are better than the euro forms with soldier system for single face walls in underground building construction. In addition, it is showed that the cost of these two forms is similar and usage the working space and safety in non-supporting system forms are better that those of the euro forms with soldier system, too.