• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1132-1137
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• 2010

There are execute of new laws about prevent of earthquake diaster in nation because of some increments of big earthquake occurence frequency. Now develope new composit plate by ductile fiber with strong mechanic materials, which compose of strengthening systems for the underground structures subject to forced displacements. This study is to focus to develop the retrofitting system for the cut and cuver tunnels built without earthquake type load scenario, so that it can provide the safety of existing urban subway system against earthquakes.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.15-19
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• 2009

Due to the Japan's Kobe earthquake in 1995, a cut-and-cover tunnel, which is one of subway facilities, collapsed unexpectedly. As a result, also in Korea, seismic performance needs to be secured for the cut-and-cover tunnel and currently, the subway seismic design standard is based on the seismic performance. However, there is no standard for the damage level or stability level of a member for securing the seismic performance, and the definition of multi-level seismic performance is not sufficient. By contrast to this situation, in the Japan's evaluation method of seismic performance, design earthquake ground motion having reflected there into the subway driving stability is clearly defined and the seismic performance required for structures is classified in detail. This study analyzes the Japan's systematic evaluation method of seismic performance for cut-and-cover tunnels of subway.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.6-9
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• 2009

The occurrence rate of the earthquake more than magnitude 5 has been increased since 1990 and the damage of the Odaesan earthquake, 2007 was serious. Due to that, one may say that Korea is not any more safe for the earthquake. Therefore, it is necessary to prepare strategies for possible damage due to strong earthquakes in future. This study is to focus to develop the retrofitting system for the cut and cuver tunnels built without earthquake type load scenario, so that it can provide the safety of existing urban subway system against earthquakes.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.125-131
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• 2008

This research tries to analyze and investigate the effects of the noise reduction test for the sound-absorbing materials installed tentatively on Metro Line 5. Though the noise reduction effects of each sound-absorbing material showed that there was about $2{\sim}5\;dB$ compared with before and after of the tentative installation, it shows that the noise reduction effects are reducing because of the section change condition such as dust absorption and the rail abrasion as time passes after the tentative installation. Also, many difficulties are occurring in the maintenance of the orbit facilities because of the installation of sound-absorbing materials. Though various abroad products for noise reduction are imported like this, the researches for the noise reduction effect increase for this and the improvement direction are being required because of the poor circumstance of the efficiency aspect compared to the economic investment effect because those are not suited to the character of domestic Metro.

• Journal of Korean Tunnelling and Underground Space Association
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• v.11 no.1
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• pp.97-105
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• 2009

This paper studied the cause of the deterioration of the four 3-Arch tunnels built in mid-1990. The common deteriorations of the four 3-Arch tunnels were longitudinal cracks, leakage and efflorescence at the same parts of lining concrete. Three fourths of 3-Arch tunnels, there was high percentage longitudinal cracks and a quarter was low frequency about longitudinal cracks. So the material reviewed to find out the differences between two groups in construction process and analysis was conducted such as non-destructive testing, precise visual survey and safety evaluation of one tunnel which had bad ground condition As the result, the tunnels were safety condition and the primary deterioration occurred during the construction process, namely, problems arrangement of rebar and the effects of the blast at middle tunnel.

• Journal of the Korean GEO-environmental Society
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• v.24 no.5
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• pp.5-12
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• 2023

Recently, due to urban development and expansion, construction plans have been increasing adjacent to existing tunnel structures such as subways, roads, and large pipelines. Structural plans adjacent to existing tunnels have different effects on tunnel stability depending on the construction method, degree of proximity, and location of new structures. In particular, the pressure water tunnel shows a very large difference from other road tunnels and railway tunnels in geotechnical characteristics and operation characteristics. Therefore, it is necessary to review the safety zone due to adjacent construction in consideration of the geotechnical characteristics of the water tunnel and the new sturure construction method. In this study, the existing tunnel safety zone standards were investigated. A stability evaluation performed numerical analysis considering the deterioration of concrete lining in operation and the characteristics of water tunnel. In addition, the impact of vibration caused by pile construction and blasting excavation of new structures was reviewed. Based on this, a pressure water tunnel safety zone was proposed in consideration of adjacent construction.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2010.04a
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• pp.514-515
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• 2010

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.4
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• pp.509-517
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• 2022

The demand for underground infrastructures such as tunnels is expanding due to rapid urbanization. Tunnels in urban areas are usually constructed adjacent to structures supported by piles. Therefore, a proper understanding of pile-tunnel interaction due to tunnel excavation activities is vital. Thus, in this study, a numerical analysis is conducted to analyze pile settlements, ground surface settlements and shear deformations above an existing tunnel subject to the presence of an adjacent tunnelling, with vertical offsets, the number of piles and the pile spacing considered as variables in the analysis. The results show that the vertical offsets between the tunnel crown and the pile tip generatelarger settlement than the pile spacing. In addition, the vertical offset shows an inversely proportional relationship to the shear deformation due to new tunnelling.

• Tunnel and Underground Space
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• v.12 no.2
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• pp.115-119
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• 2002

Four tunnels have been planned to operate a large diameter shielded TBM in Gwangju urban subway construction site. No.1 tunnel has completely been excavated for 13 months operating. Net penetration rate and its relations with thrust farce of the shielded TBM are analysis in this report. This shallow depth tunnel of 536m length is located in soil layers at launching and in hard rocks at ending with 84 m length. The weekly net penetration rates haute dropped down as low as 20∼110 mm/hr in rock while 400∼800 mm/hr in soil. The actual penetration rates we proved to be high as the theoretical penetration rate which is analysis in consideration of conditions of machine and rock. And net penetration rate is investigated to increase linearly thrust force.

• Journal of The Korean Society For Urban Railway
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• v.6 no.4
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• pp.339-350
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• 2018

The rail wear measurements in urban underground railway have been analyzed to predict the particulate matter emission caused by rail wear which is one of the major sources of particulate matter emission for underground railway systems. From the rail profile variations measured in the interval of one and half year by dedicated rail wear measuring instrument over the commercial urban underground railway line, 'line-s' which is about 45km long, the characteristics as well as the amount of rail wear have been analyzed after dividing the whole line into about 170 section with radius of curve(R). It has been concluded that the vertical wear parameter V0 and corner wear parameter C0 have been selected to represent the wear amount of straight and curved rail respectively. The amount of rail wear as well as the particulate matter emission by rail wear over the whole line normalized by the rail length as well as the number of train has also been deduced from the relationship between the rail wear parameters and the amount of rail cross-section area.