• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.11a
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• pp.418-418
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• 2004

• Clean Technology
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• v.26 no.1
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• pp.13-21
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• 2020

Air pollutants in a subway are complexly caused by outdoor factors such as ventilating opening and indoor factors such as the movement of passengers on the subway. According to recent research results, most of the air pollutants generated in subway tunnels and stations are caused by indoor variables such as train movement. To control air pollutants such as particulate matter (PM), a prevention facility such as the electrostatic precipitator (EP) or bag filter collector was required in a subway station. In particular, the PM removed by the EP must be kept clean continuously to manage PM effectively. Therefore, a nano-bubbling washing system was developed in this study to clean a contaminated collecting plate in an EP at the main subway tunnel in Seoul. Removal efficiency compared with normal water and nano-bubbling water was likewise studied. As a result, the washing efficiency of collective PM increased in accordance with the increasing of injection pressure, with nano bubbling washing being 130.8% higher than tap water. According to increase in washing times, the maximum washing efficiency was 143.1% higher than tap water, but suitable washing times were less than 3 times. According to the results of the washing efficiency by variation of residence time, it was confirmed that the maximum residence time of nano-bubble water was maintained within 5 minutes.

• Proceedings of the Korean Society for Rock Mechanics Conference
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• 2001.10a
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• pp.115-120
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• 2001

In No. 1 tunnel for Kwnagju urban subway construction, net penetration rate of the shield TBM was analyzed. This tunnel of 540 m length is located in soil layers at starting and in hard rocks such as amphibolite and granitic gneiss at ending with 84 m length. The net penetration rate was dropped down to 2∼11 cm/hr in rock while 50∼80 cm/hr in soil. Theoretical penetration rate is analyzed in conditions of machine and rock in order to compare the actual net penetration rate. The relationships between net penetration rate and thrust force is also investigated in this report.

• Proceedings of the Korean Geotechical Society Conference
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• 1995.10a
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• pp.25.2-38
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• 1995

the Effect of steel pipe reinforced multi-step grouting(SPRG) technique to inrove the ground far ahead of the excavation face was investigated by means of numerical analysis. It was found taht the nonlinear 3-D FEM program performed well to evaluate the usefulness of the SPRG technique in soft ground tunnelling, and about 20% of settlement control in this particular case possible. Therefore in urban subway tunnel construction, the New Austirial Tunnelling Method can be satisfactorily applied even in poor ground conditon with aid of the SPRG technique.

• Journal of the Korea Construction Safety Engineering Association
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• s.54
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• pp.41-55
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• 2011

The current railway projects under plan, design, or construction have been designed as 'very long and deep underground tunnel'. Therefore, it is reasonable that the standards for preventing disaster in such conditions should be intensified in order to avoid repeating the same failure which happened in Daegu subway disaster, Although we consent to the opinion that nothing can compete with human being's life, it is very difficult to protect the life from all of potential disasters perfectly in railway fields because the excessive standards can result in excess construction cost, which can bring about cancelation of the project itself eventually. Therefore optimized disaster design standard is required to negotiate the conflict between economical cost and social tolerance limitation simultaneously.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.192-195
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• 2006

With increasing concerns of indoor air quality, $CO_2$ concentration in the public transportation, such as train, bus, and subway, draws big interests. The $CO_2$ concentration in the indoor air is regarded as index of ventilation status rather than that of adverse health effect. In this study, we measured the time-series of $CO_2$ concentrations in the KTX cabin during the journey of Gyongbu-line (Seoul-Busan) and Honam-line (Seoul-Mokpo) with the number of passengers on board. At the same time, the concentration of particulate matter (PM), temperature, humidity and gaseous pollutants including HCHO and VOCs were monitored. It is found that the $CO_2$ concentration was correlated linearly with number of passengers and was highly correlated with tunnel regions where the ventilation unit (flap) was closed.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.03a
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• pp.679-686
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• 2002

A substantial portion of the cost of a tunnelling project in urban environments is, therefore, devoted to prevent ground movement. Therefore, prediction of ground movements and assessment of risk of damage to adjacent buildings has become an essential part of the planning, design, and construction of a tunnelling project in the urban environments. An internet-based tunnelling-induced ground movements and building damage assessment system (IT-TURIMS) was developed and implemented to Daegu Metro Subway Line tunnel construction project in Korea. This paper describes the concept and implementation of IT-TURIMS. Practical significance of tunnelling risk assessment is also discussed.

• Journal of the Korean Society for Railway
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• v.13 no.2
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• pp.194-200
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• 2010

Recently, a longitudinal tunnel construction has increased because of subway construction extension, geomorphological effect and the development of construction Technologies etc. When the fire occurs in a tunnel and an underground structure, the many damage of human life and the economic losses are caused. In Korea, fire resistance character study of a tunnel and an underground structure is proceeding. However, when a concrete is exposed to high temperature, study of load carrying capacity reduction and stability evaluation for spalling of a concrete is not enough. Therefore in this study, fire resistance character of a concrete evaluated according to time heating temperature curve(RABT and RWS) and a result compared on virtual fire accident in order to apply fire scenario. Also this study performed thermo-mechanical coupled analysis of a FEM-based numerical technique and estimated fire-induced damage of a tunnel and an underground structure.

• Journal of Korean Tunnelling and Underground Space Association
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• v.7 no.3
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• pp.219-226
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• 2005

The result that analyze for 6 years a groundwater influx quantity of total 60 catch-pit established in subway line 5 appeared with $0.77m^3/min$. When comparing design approaches of the catch-pit with design approaches of the box structure $2m^3/min$ and the tunnel structure $3m^3/min$, it is found that it has a surplus. Red sedimentation substance contains large portion of Fe. The earth retaining structure of a tunnel and groundwater containing more portion of Fe than other area rue the major factor of this substance. In case of white sedimentation substance, the most frequently founded ingredient is CaO, which is occurred in case grouting injection materials for ground reinforcement is transmitted into a tunnel system by ground water. This substance is doesn't affect safety of a tunnel.

• Journal of Industrial Technology
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• v.24 no.A
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• pp.227-238
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• 2004

This paper is results of experimental and nunerical works on the behavior of the cut-and-cover tunnel. Centrifuge model tests were performed to simulate the behavior of the cut-and-cover tunnels having cross sections of national road and subway tunnels. Model experiments were carried out with changing the cut slope and the slope of filling ground surface. Displacements of tunnel lining resulted from artificially accelerated gravitational force up to 40g of covered material used in model tests, were measured during centrifuge model tests. In model tests, Jumunjin Standard Sand with the relative density of 80 % and the zinc plates were used for the covered material and the flexible tunnel lining, respectively. Basic soil property tests were performed to obtain it's the property of Jumumjin Standard Sand. Shear strength parameters of Jumunjin Standard Sand were obtained by performing the triaxial compression tests. Direct shear tests were also carried out to find the mechanical properties of the interface between the lining and the covered material. Numerical analysis with the commercially available program of FLAC were performed to compare with results of centrifuge model experiment In numerical modelling. Mohr-Coulomb elasto-plastic constitutive model was used to simulaye the behavoor of Jumunjin Standard Sand and the interface element between the lining and the covered material was implemented to simulate the interaction between them. Compared results between model tests and numerical estimation with respect to displacement of the lining showed in good agreements.