• Journal of the Korean Society for Railway
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• v.15 no.4
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• pp.381-387
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• 2012

This paper is aimed to analyze the achievements of the Tunnel Monitoring System(TMS), implemented in Seoul subway L5~L8, and to find out improved methods. By introducing the TMS, it is possible to inspect tunnel facilities for 24 hours a day while trains are operated. The inspection capability could be expanded, the accuracy was improved, and the cycle was shortened. The efficiency of manpower was improved and the surplus manpower could be used for other tasks of facilities maintenance. As a result, by introduction of the TMS, the amount of tunnel maintenance was increased by 225% and the train service troubles caused by facility problems were decreased by 53%.

• Explosives and Blasting
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• v.25 no.1
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• pp.1-14
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• 2007

A blasting noise generated by blasting work, which is a kind of shock-noise, influences the human body. A civil appeal due to blasting noise causes work discontinuance and downsizing of a blasting scale. Most of soundproof facilities for reducing a blasting noise is installed at each working spot by itself and the degree of a noise reduction is very low. The aim of this study is to recommend a technology on noise reduction considering the method and material of soundproof facilities. As the first study step to acquire basic data, investigations on the installation time, installation method, and material of the soundproof facilities have been done at about 20 tunnel work spots such as railroad tunnel, road tunnel, tunnel for electric power.

• Proceedings of the KSR Conference
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• 2003.10b
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• pp.265-270
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• 2003

Though the probability of tunnel fire accident is very low, but critical fatalities are expected when it occurred. In this study the effect of critical safety parameters on tunnel fire accident are examined using probabilistic technique. Fire detection time, smoke spread velocity, passenger escape velocity, flash-over time, and emergency service arrival time are considered. In order to estimate the uncertainties of input parameters Monte Carlo simulation are used, and fatalities for each assumed accident scenarios are obtained as results. For the efficiency of iterative calculation PRA(Probabilistic Risk Analysis) code is developed in this study. As a result fire detection have large effect.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1963-1969
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• 2009

This paper introduces method to estimate pollutant negative influence to polymer type insulator according to the international standard. To accomplish this goal, effective sample collecting method was surface was collected directly with the same dimension. Distilled Through this method pollute is easily and accurately collected. The second step is pollutant analysis. Several analyze item is selected such as quantity, conductivity, contact angle, Optical Microscope(OM), IR spectrometer(FT-IR), Equivalent Salt Deposit Density(ESDD), Thermal Analyzer(TA) and ICP-AES. The third step, best represent tunnel was selected considering location, length and natural surroundings. Also to consider the difference at inside the tunnel, several bracket insulators were selected along to the location. To make the result precise, above procedure was repeated several times at the same target. Finally relation among type of train, numbers of movement, surroundings, length will be considered in combination with the pollution. With this result pollute map for KORAIL could be accomplished and inspect period will be optimized case by case.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1838-1844
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• 2007

The Wonhyo Tunnel on KTX railroad line is a section of latest concerns from domestic environmental NGOs, which focus on potential destruction of ecosystem or the like due to ever-depleted swamp water at about 300m upward from the tunnel under construction. As a result of study, out of all swamps in the vicinity of the tunnel, it was found that Mujechi 1st and 2nd swamps have been getting smaller in their area little by little since 50 years ago primarily under the influence of eroded streams around lower swamp and even ever-increasing annual mean temperature. As the result of monitoring about swamp before work, it was found that swamp water depends absolutely on amount of rainfall. Besides, the results of monitoring during work also didn't show any leakage generated in the tunnel during and after excavation works with regard to a wheat field swamp in the most vicinity of the tunnel (80m away). On the other hand, it was found that the range affected by ground water sink in tunnel section without grouting process amounted to about 100m around the tunnel, which indicates that such ground water sink has no significant impact upon most of swamps near the tunnel. As the result of testing by two well tracer test around swamps, it was noted that swamp water didn't run out from the bottom of swamp even with adjacent ground water level sunk in factitious ways. And the results of physical survey showed that swamp kept saturated even in dry season when ground water level becomes lower than the bottom of swamp. Therefore, even supposing that ground water level becomes sunk due to tunnel works, it is estimated that the water level of swamps would be still kept owing to impervious layer(peat beds).

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.5
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• pp.773-786
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• 2018

In this paper, viscosity features of sealant (bentonite-cement slurry), which is used for umbrella arch method in tunnel, were studied. The sealant must secure optimal strength and capacity for the waterproof and stabilization of borehole as well as to satisfy groutability. In this study, the variation of viscosity was measured with different mixing processes. With an increase of initial mixing period with water and bentonite mixture, the required time for the rapid increase of viscosity of the sealant is shorten. With increase of mixing period, the possibility of swelling of bentonite will increases and this can lead increase of the viscosity of the mixture. In addition, the behaviors of sealant vary with a drastic increase of the viscosity: thixotropy and rheopexy. Furthermore, the bentonite/water mixing period influences on the bleeding features of the sealant. Further study is required to introduce the guideline, which can be applicable in the field in the aspect of required capacity of the sealants and mixing processes of the ingredients.

• Fire Science and Engineering
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• v.26 no.3
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• pp.1-7
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• 2012

When the subway car stop on track, passengers have to overcome a height of 1.2 m from floor level of the subway car to the level of track for evacuation. In this experiments, participates in the group of twenties or under ages were rapidly jumping down from the subway car. However, Most elderly group were not easy to overcome the height without help of others and some of them were fell and injured. In case of merging flows, the flow rate of the group of twenties was lower than the other cases. If fire occurred in the train and train stopped in the tunnel, it will be needed a lot of total evacuation time because of the heigh difference and wall effect from subway car to outside.

• Tunnel and Underground Space
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• v.18 no.6
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• pp.393-407
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• 2008

To protection of fire accident and to minimize danger of spreading the disaster. in railway tunnel, MCT (the Ministry of Construction and Transportation) published "Rules about the Safety Standard of Railroad (2005.10.27)" and "The Detailed Safety Standard of Railroad (2006.9.22)". QRA(Quantitative Risk Analysis) results are applied to establish the fire protection facilities in railway tunnel so that institute the reasonable application about the fire safety facilities However, it is difficult to perform the fire safety design due to lack of the detailed standards about event scenario, fire intensity, incidence rate of accidents etc. Therefore, This paper introduces the practical method about detailed standards of QRA.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1964-1969
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• 2010

Recently, as construction market scale is getting bigger and transportation industry is developing, the underground structure construction such as subway, tunnel (excavation box) or shield tunnel structure is becoming more diverse, and its demand is gradually increasing. However, for the concrete structures constructed underground, the water leakage is occurred due to the expansion joint and construction joint, or movement, uneven settlement, excessive load and vibration during application causing cracks. Many waterproofing method and materials are used in jobsites, but areas such as underground railroad and subway that has movement and vibration at all times, the ability of waterproofing layer is declined causing repetitive water leakage due to crack, erosion and separation, which is a vicious cycle. Therefore, this study evaluates the responsiveness to a movement for adhesive/flexible waterproofing material that can cope with the vibration and the movement of the structure. Also to recommend a waterproofing technology that can cope with structure movement through examples of actual jobsite applications such as subway and tunnel where there are constant movement and vibration.

• Journal of the Korean Society for Railway
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• v.18 no.6
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• pp.567-577
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• 2015

This paper presents an assessment method of the ground vibration level with a combination of measured data and an analytic method. The basic concept of the method is similar to that in FRA(Federal Railway Administration) manual for detailed vibration analyses. However, going into detail, the assessment method was modified for a feasible evaluation of the vibration reduction effects of diverse types of wave barriers. The force density was evaluated in a vehicle-track interaction analysis and the transfer mobility of vibration was analyzed through a 2-D ground vibration analysis. The calculated 2-D transfer mobility was corrected to incorporate transfer characteristics of actual ground vibration by comparing the previously measured data and analysis results. Nine types of vibration reduction effects of wave barriers were analyzed on a shallow tunnel section of an urban railway where numerous civil complaints had actually been filed.