• Journal of the Korean Society for Railway
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• v.10 no.6
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• pp.766-771
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• 2007

In this research, we were going to make the function which can forecast the operating cost of metropolitan railroad that is performing a role of assistant highway within the city. In order to do this, based on service records of subway line 1st to 8th in Seoul, we extracted 23 variables which can affect to the operating cost, and we selected the final variable for estimate the function of operating cost from correlation among variables and influence analysis. Then, we performed regression analysis by stages using final variable. 6 independent variables are chosen for presuming the operating cost, and we obtained the final 3 variables (quantity of holding motor cars, peak quantity of possessed motor cars, and quantity of stations) as a result of regression analysis. Through this research, function of operating cost of metropolitan railroad has better applicability than existing preliminary validity, and it is used by further preliminary validity investigation and master plan or validity investigation which is accompanied by operation designing, thus we expect that it could make a great contribution to the priority order of investment for metropolitan railroad or process of policy decision.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.1046-1053
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• 2006

In the large scale recent reclaiming works performed within the wide spatial boundary, evaluation of long-term consolidation settlement and residual settlement of the whole construction area is sometimes made with the results of the limited ground investigation and measurement. Then the reliability of evaluation has limitations due to the spatial uncertainty. Additionally, in case of large scale deep excavation works such as urban subway construction, there are a lot of hazardous elements to threaten the safety of underground pipes or adjacent structures. Therefore it is necessary to introduce a damage prediction system of adjacent structures and others. For the more accurate analysis of monitoring information in the wide spatial boundary works and large scale urban deep excavations, it is necessary to perform statistical and spatial analysis considering the geographical spatial effect of ground and monitoring information in stead of using diagrammatization method based on a time-series data expression that is traditionally used. And also it is necessary that enormous ground information and measurement data, digital maps are accumulated in a database, and they are controlled in a integrating system. On the abovementioned point of view, we developed Geomonitor 2.0, an Internet based real time monitoring program with a new concept by adding GIS and geo-statistical analysis method to the existing real time integrated measurement system that is already developed and under useful use. The new program enables the spatial analysis and database of monitoring data and ground information, and helps the construction- related persons make a quick and accurate decision for the economical and safe construction.

• Journal of the Korean Geotechnical Society
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• v.31 no.10
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• pp.29-36
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• 2015

This paper deals with inspecting and monitoring cracks developed on a subway tunnel liner during the construction of temporary supports and excavation. The cracks have developed near a enlarged part of the tunnel. Several measurements, crack gauge, internal displacement measurement, 3-D laser scanner have been conducted to monitor the progress of cracks and effects of them on the tunnel. Local measurement, additional propagation of cracks and deformation of liner, have been conducted by crack gauge and internal displacement measurement. Global inspection has been conducted by 3-D laser scanner. From the scanned data, occurrence of global deformation of tunnel and rail has been evaluated. Because of limited sequence of construction at the ground, no apparent deformation of crack propagation has been measured. As presented in this paper, deformation of tunnel liner and effects of rail need to be investigated in view of local and global aspects.

• Journal of the Korean Society of Safety
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• v.21 no.5 s.77
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• pp.22-27
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• 2006

Even though the interior of urban transit vehicle has been changed as a preventing measure against fire to make it inflammable, there remains a possibility of fire breaking out in case of gasoline etc being brought in the subway. However, there is also the possibility that in case if fire toxic gas is generated and hot air spreads in carriage it will prove very dangerous for people sitting inside. This is a comparative study where we compare simulation results with model examining the time and direction the fire spreads when it breaks out. Also there is vertical distribution of temperature in carriage where the fire spreads out. This study is about demonstrating how to establish smokeless system in urban vehicle, about its necessity, and about vehicle system restructuring. This study also makes an effort to find more advanced method for efficient fire safety in trains. In existing vehicles, in case of fire, the smoke can't go out when doors are closed and hence it spreads in whole train. Even though the method of using ventilation or exhaust established inside the carriage to throw smoke out is much better than the way of opening end doors in each carriage, this study is trying to do research on second way. Through simulation we see that in second case, even though not as good as the first one, smoke can exit through gates. Even though the first method is better, the second can also be uses to let fire out. We can know that in the first case as the smoke can exit out faster, it provides more safety for people. So this system provides better fire safety condition.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.04a
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• pp.618-626
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• 2011

Recent development of related technologies and efficient utilization of the entire country for the purpose of railway construction, and plans are being accelerated. the railway noise has been improved by increasing the high speed railway station, and accelerating the existing trains. Nord2000 which is an overseas noise prediction equation could not be applied directly to the domestic railway vehicles. So the specific vehicles in the Nordic countries which is a similar specification to domestic trains should be selected. Nord2000's accuracy was compared to Schall03, CRN's. Prediction of Ground impedance and Roughness class were carried out at different. In this paper, the result of selected vehicles for Nord2000 was as follows. S-1aX2 was for express trains, N-$^*2c$-3b was for Mugunghwa, S-Pass/wood was for Saemaul, N-4a was for freight trains, N-3a was for subway, the calculation time for Nord2000 took longer than others, in addition, Ground absorption was indispensable to calculate a noise map for Nord2000. As a result, CRN's prediction noise levels at Wonju-si was closest to the measurements. However, the predicted noise levels of Nord2000 was the most accurate.

• Journal of the Korean Society for Railway
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• v.20 no.5
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• pp.612-624
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• 2017

As the existing metropolitan area metropolitan railway operates on a one-to-one basis, which leads to long travel times, its competitiveness with other means of transportation is deteriorating. Since there is a limit to attracting road traffic by rail, there is a continuing societal demand to expand express train service. Especially in the northern and the southwestern parts of the metropolitan area, a public transportation network system with express function, connecting to the city center of Seoul, is needed because of the social cost of the increase of traffic congestion and the increase of the travel time. The most efficient express service in Korea is Seoul Subway Line 9, which runs in 27 minutes from Gimpo Airport to the high speed terminal; this is a 40% shorter time compared to 44 minutes by car; the congestion in this area is up to 240%, so the preference for this train is quite high. The technical results of this study are expected to contribute to the implementation of an express service metropolitan railway.

• The Journal of the Convergence on Culture Technology
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• v.6 no.1
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• pp.477-483
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• 2020

The rehabilitation methods used in existing concrete box structures rely on the method of attaching the repair material to the section of the structure with a spray equipment. In the case of ceiling or wall parts, the adhesion force to the repair material may be reduced by the gravity and dead load after construction. In subway structures, vibration causes a problem that reduces the initial adhesion. Supplementary measures are needed as the quality of repair varies depending on the worker's proficiency and construction environment. In this study, mechanical pressurization equipment was developed that can apply a certain pressure after construction of a repairwork to solve problems such as reduction of adhesion of repair materials by gravity and variation of repair quality by labor work. To find out the effect of the pressurized equipment, a chamber similar to the field conditions was constructed to measure the attachment strength different from the pressurized condition, the section, and the environmental conditions. The pressurization differed from the other parts, but the adhesion strength of up to 70% was increased.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.4
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• pp.1817-1823
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• 2011

OFDM Modulation is used for multimedia transmission At Urban Train. Recently the application field about data transmission is expanding the image as well. The case which the number of OFDM carrier is big is advantageous because multipass fading is big 18GHz wireless frequency. Existing WLAN which an ethernet transmission is possible is not suitable to a great distance transmission because number of carrier is 64. In this paper, we developed OFDM modem suitable to transmit broadband data at high speed train. A doppler compensation block added to offset the doppler effect. Therefore, the effectiveness is expected to be very big in field of urban train.

• Journal of the Korea institute for structural maintenance and inspection
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• v.7 no.3
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• pp.215-222
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• 2003

Recently the deep and large excavations are performed near the existing buildings in urban areas for the practical use of underground space. The earth pressure due to the excavation are varied according to the conditions of ground, the depth of excavation, the construction methods, and the method of supporting the earth pressure etc.. In this study, not only the behavior of axial load and distribution of earth pressure on the flexible wall according to stage excavation depth but also magnitude and distribution of lateral deformation, and the equivalent earth pressure from strut axial loads were analyzed by the results measured from instruments such as, load cells, strain gauges, and in-situ inclinometer, on the field of subway construction. According to the results of this study in the case of stage excavation the earth pressure of soft clayey soil is compounded with Terzaghi-Peck and Tschebotarioff.

• Geomechanics and Engineering
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• v.34 no.1
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• pp.17-27
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• 2023

Taking a subway shield tunnel in a certain section of Zhengzhou Metro Line 5 as an example, the field tests of shield cutting cement-soil monopile composite foundation were carried out. The load and internal force of the tunnel lining under the action of composite foundation were tested on-site and the distribution characteristics and variation laws of earth pressure around the tunnel under the load holding state of the composite foundation were analyzed. Five different load combinations (i.e., overburden load theory + q₀, Terzaghi's theory + q₀, Bierbaumer's theory + q₀, Xie's theory + q₀, and the proposed method (the combination of compound weight method and Terzaghi's theory) + q₀) were used to calculate the internal force of the tunnel structure and the obtained results were compared with the measured internal force results. The action mode of earth pressure on the tunnel lining structure was evaluated. Research results show that the earth pressure obtained by the calculation method proposed in this paper was more consistent with the measured value and the deviation between the two was within 5%. The distribution of the calculated internal force of the tunnel structure was more in line with the distribution law of field test data and the deviation between the calculated and measured values was small. This effectively verified the rationality and applicability of the proposed calculation method. Research results provided references for the design and evaluation of shield tunnels under the action of composite foundations.