• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.249-252
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• 2006

Recently, as it has greatly increased the demand on the serviceability of subway, cable tunnel and underground storage, the stability of tunnel structures has been attracting the concern of engineers and researchers. Thus the aim of the present study is to evaluate acid attack resistance of shotcrete using in tunnel structures. And, in order to understand the deterioration mechanism, test using scanning electron microscopy(SEM) analysis and X-ray diffraction showed that the deterioration mechanism due to acid attack in shotcrete.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.25 no.1
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• pp.7-13
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• 2016

With the increasing running speed of trains, new railway lines in metropolitan areas, and the rising demand for green transportations, the number of underground and tunnel sections are constantly becoming larger, and installations of overhead rigid conductor systems are becoming wider. However, domestic commercial products for overhead rigid conductors are limited to 120 km/h train speeds. In this study, to develop a high-speed (250 km/h) overhead rigid conductor, R-Bar (Rigid Bar), the electrical and mechanical stability was enhanced through the improvement of the cross sectional shape of the R-Bar; the transition structure was also designed for flexibility and natural frequency isolation. In addition, the evaluation of contact forces between a pantograph and the overhead rigid conductor system for 250 km/h train speeds was performed using dynamic analysis.

• Journal of Korean Tunnelling and Underground Space Association
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• v.6 no.4
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• pp.345-356
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• 2004

Open-cut method has been widely used to construct underground structures, but it causes several problems such as traffic congestion and public resentment resulting from severe construction noise and ground settlement. In many cases, it is very difficult to build underground structures safely due to the unknown locations of buried facilities such as water pipes, drainage pipes, gas pipes and high-pressure cable conduits etc. Also in open-cut method, moving buried facilities causes additional cost and extension of construction period. Therefore, this paper is to present a case study in which Tubular Roof construction Method (T.R.c.M.), a newly developed construction method for underground structures using slab steel pipes and PC wall trench, is applied for the construction of a subway tunnel in Seoul. As a result, it is found that T.R.c.M. is a construction method by which tunnels can be constructed safely without any effect on the surrounding environment and traffic flow due to the minimized construction vibration and noise.

• Journal of Korean Tunnelling and Underground Space Association
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• v.25 no.3
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• pp.201-220
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• 2023

Power cable tunnels is one of the underground structures meant for electricity transmission and are constructed using shield TBM method when transitting across urban and subsea regions. With the increasing shaft depth for tunnels excavation when the shield TBM excavated the rock mass, the review of selecting closed-type shield TBM in rocks becomes necessary. A simplified shield TBM design method is also necessary based on conventional geotechnical survey results. In this respect, design method and related design program are developed based on combined results of full-scale tests, considerable amount of accumulated TBM data, and numerical simulation results. In order to validate the program results, excavation data of a completed power cable tunnel project are utilized. Thrust force, torque, and power of shield TBM specification are validated using Kernel density concept which estimates the population data. The robustness of design expertise is established through this research which will help in stable provision of electricity supply.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.245-248
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• 2006

This study investigated the strength of shotcrete with aluminate accelerator to connect with the proper repair methods or monitoring skills in subway, cable tunnel and underground storage. In order to approach these goals, the shotcrete specimens were exposed to acid, sulfate and seawater environments, and strength properties of the shotcrete suffering from the attacking sources were examined.

• Proceedings of the SAREK Conference
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• 2003.07a
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• pp.243-243
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• 2003

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.10
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• pp.577-582
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• 2000

This paper analyze the interference problems, especially Ac corrosion 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(inductive coupling, conductive coupling, resistive coupling), AC corrosion, limitation of safety voltage, modeling of power cables, gas pipeline and grounding systems, analysis of induction voltage and optimal arrangement of power cables.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.2
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• pp.74-79
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• 2002

We have been analyzed the interference problems already in steady state, especially AC corrosion when the gas pipeline is burred with power cable in the same submarine tunnel. In the next stage, we analyze the induced voltage in a fault condition of 154[kV] underground T/L. This paper presents the results of them which are limitation of safety voltage. meodeling of power cables, gas pipeline and grounding systems, analysis of induced voltage in a fault condition, and protection of Power line system.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.605-614
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• 2010

In this paper, the initial behavior of transmission tower was analyzed. This tower was firstly constructed by rock anchor foundation in domestic 154 kV transmission line and wireless real-time monitoring system was installed to obtain the measured data for analysis of the structure behavior. For this purpose, 16 strain gauges was installed in anchors of foundation and strain gauges, clinometers, anemoscope and settlement sensors was installed at superstructure. As the results, the main factor which influence the behavior of superstructure is wind velocity, wind direction, rainfall and temperature change. Especially, the uplift load at stub of transmission structure revealed about 35.4 percentages of design load. Hereafter the long term stability will be analyzed.

• Journal of electromagnetic engineering and science
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• v.14 no.2
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• pp.79-81
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• 2014

In B-scan data measured by a pulse-type monostatic borehole radar, target signatures are seriously obscured by two clutters that differ in orientation and intensity. The primary clutter appears as a nearly constant time delay, which is caused by internal ringing between antenna and transceiver in the radar system. The secondary clutter occurs as an oblique time delay due to the guided borehole wave along the logging cable of the radar antenna. This issue led us to perform adaptive filtering processing for orientation-based clutter removal. This letter describes adaptive filtering processing consisting of a combination of edge detection, data rotation, and eigenimage filtering. We show that the hyperbolic signatures of a dormant air-filled tunnel target can be more distinctly enhanced by applying the proposed approach to the B-scan data, which are measured in a well-suited test site for underground tunnel detection.