• Journal of the Korean Society for Railway
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• v.19 no.5
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• pp.576-584
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• 2016

In this study, we measured the air tightness of a train using pressure variation in tunnels. To estimate the air tightness of a train is essential to comprehend the pressure variation of the cabin because air tightness is strongly related with ear discomfort. If we can determine the air tightness, we can predict the pressure variation of the cabin. Also, ear discomfort is a problem that can be caused in a high speed train, as well as in Korea's Great Train Express. In this study, we compared the various international standards for ear discomfort and estimated the air tightness of each vehicle based on experimental data obtained using the ITX, KTX and KTX-sancheon(honam) vehicles. The internal pressure variation of the trains is numerically calculated using the air tightness value. The results are good compared to the experimental results. Instead of flap type ventilation, in the future, continuous ventilation equipment will be needed for speed-up.

• Journal of the Korean GEO-environmental Society
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• v.11 no.2
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• pp.43-52
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• 2010

Shield method is the tunnel boring method that propels a steel cylinder in the ground and excavates tunnels at once. After Marc Isambard Brunel started using the method for the Thames Riverbed Tunnel excavation in London, many kinds of TBM (Tunnel Boring Machine) developed and applied for the construction of road, railway, electricity channel, pipeline, etc. In comparison with NATM concept that allows to observe ground condition and copes with difficulty. The machine selected before starting construction is not able to be changed during construction in shield TBM. Therefore the machine should be designed based on the ground survey result and experiment, so that the tunnel might be excavated effectively by controlling penetration speed, excavation depth and cutter head speed according to the ground condition change. This research was conducted to estimate penetration depth, excavate speed, wear of disc cutter on Boondang Railway of the Han Riverbed Tunnel ground condition by TBM performance prediction models such as NTNU, $Q_{TBM}$, Total Hardness, KICT-SNU and compare the estimated value with the field data. The estimation method is also used to analyze the reason of poor excavation efficiency at south bound tunnel.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1D
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• pp.125-132
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• 2006

In the present study, in order to elucidate the vibration characteristics of track and train body according to the type of track in tunnel, the vibration accelerations of the track and the KTX train body have been measured in tunnels of Kyong-Bu high-speed railway(HSR) lines, and the frequency analysis of the measured data has been performed. From this, the vibration characteristics of the track components such as rail, sleeper, ballast and slab, the tunnel lining and the vehicle body according to the type of track are investigated and their relation is analyzed. The test results show that the vibration of rail and vehicle body rapidly increases at 80Hz in tunnel, and that is much higher in the tunnel on which the concrete slab track is placed. According to the results of the present study, rail supporting stiffness can variate the vibration characteristics of the total system including the vehicle, and therefore the correlation between the vibration of vehicle should be taken into account to determine the supporting stiffness of the slab track.

• Geomechanics and Engineering
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• v.13 no.1
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• pp.173-194
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• 2017

Access shaft is of critical importance to the construction and operation of underground rock caverns. It usually has a relatively large cross-section and penetrates through fill materials, soil layers, and weathered rocks before reaching the caverns excavated in solid bedrock. In this paper, the design and construction of vertical shafts are reviewed in terms of diameter, depth, geological conditions, and support structure. Three shaft alternatives, namely alternative I: vertical shaft with spiral roads, alternative II: upper shaft with spiral roads & lower tunnels, alternative III: plain shaft, are proposed based on a simplified geological profile of the Jurong formation, Singapore. The advantages and limitations of the three types of shafts are discussed. The key issues relating to shaft design and construction, such as the shaft sinking, water control, support structure, are also discussed with a series of solutions provided, such as the sequential excavation, pre-grouting and diaphragm walls.

• Journal of Environmental Science International
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• v.24 no.12
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• pp.1691-1703
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• 2015

When constructing tunnels, it is important to understand structural, geological and hydrogeological conditions. Geumgeong tunnel that has been constructed in Mt. Geumjeong for the Gyeongbu express railway induced rapid drawdown of groundwater in the tunnel construction area and surroundings. This study aimed to analyze groundwater flow system and baseflow using long-term monitoring and groundwater flow modeling around Geumgeong tunnel. Field hydraulic tests were carried out in order to estimate hydraulic conductivity, transmissivity, and storativity in the study area. Following the formula of Turc and groundwater flow modeling, the annual evapotranspiration and recharge rate including baseflow were estimated as 48% and 23% compared to annual precipitation, respectively. According to the transient modeling for 12 years after tunnel excavation, baseflow was estimated as $9,796-9,402m^3/day$ with a decreasing tendency.

• Tunnel and Underground Space
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• v.13 no.4
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• pp.260-269
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• 2003

In order to introduce to engineers the suitable calculation techniques of TBM advance rate (ad.) and ultimately promote to understand the designing process, this study was carried out. We analyzed the 17 bored data of TBM which applied to the roadway and water supply tunnels in Korea. From this analysis, it was able to how that the average utilization is 30.83% md the correlation equation of Ad and TBM´s diameter (D) is Ad(m/month) = 506.05ㆍ $e^{-0.1162}$$\times$D than the correlation coefficient ($R^2$) is 0.76. In the object of the W tunnel of Seoul-Busan highspeed railway, the Ad of TBM 5.0mø was analyzed by the variety of empirical models and upper correlation equation. Average Ad of the empirical models was calculated to be larger than one of the upper equations. But considering only the results of 3.0~5.0mø TBM in the 17 bored data, the average Ad by the models belongs to the similar range of bored data. Therefore, when the reliability and representative of parameters are decreased, a reliability test should be carried out through the comparison a variety of empirical models with the upper correlation equation.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.980-987
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• 2006

Recently, twin-tunnel is often designed considering the aspects of disaster prevention and economic reasons. However, the design cases and the studies are relatively insufficient. By the twin-tunnel excavation, deviate stresses of pillar between tunnels are increased and the increased stresses induce the instability of the twin-tunnel. In this study, numerical analyses about the twin-tunnel behaviour are conducted while varying ground strength, width of pillar and depth of earth cover and a series of regression analyses are carried out by using the results of numerical analyses for the twin-tunnel. Based on the numerical analyses, an estimation method of derived stresses is suggested though the regression analyses. Also, based on the results of regression analyses, an quantitative estimation method considering the reinforcement effects is also suggested. Then various parametric studies are conducted to be considered the reinforcement type and various design parameters. Finally, the efficiency of the suggested method is verified through the results of parametric studies.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.468-476
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• 2007

Generally, the strength of the field shotcrete is heavily dependent on the field mixing and spraying conditions so that it is different from the strength of the shotcrete mixed in laboratories. As a support member, the early strength of shotcrete unlike concrete as structural material is very important to the initial stabilization of the excavation face in tunnels. Therefore, the field methods to efficiently test the early strength of shotcrete have been highly required. This paper aimed to verify the pneumatic pin penetration test and the point load test for measuring the early strength of the field shotcrete. Through a series of uniaxial compression, pin penetration, and point load tests for the range of the early shotcrete strength, two equations to estimate reliably the uniaxial compressive strength by the pin penetration and the point load tests were derived. Field tests in working tunnel were carried out in order to estimate the economic efficiency. As a result, pin penetration method was proved to be the most effective method for testing the early strength of the field shotcrete.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1882-1889
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• 2007

Surveying rocks for engineering aims for prediction of geological feature of the construction site. Conventionally, survey information at outcrops and bore holes are projected to the construction sites, such as tunnel and slopes, and rock properties of the sites are predicted by interpretations of specialists. This system, the "Fracjection", aims to assist the specialist for visualization of the projected fractures from borehole and outcrop survey. The Fracjection accepts the BIPS and outcrop survey data to its database and allows plotting them in AutoCad map. The software also reads elevation data from contours of the topographic map and constructs DEM of the construction sites. With user's guide, it generates 3D excavation sites such as slopes and tunnels at the topographic map. The s/w projects borehole and outcrop surveyed fractures onto the modeled excavation surface and allows analysis of failure criteria, such as plane, wedge, and toppling failures by built-in stereonet function. Projected fractures can further be analyzed for structural homogeneities and rock mass quality. Moving window style correlation comparison of stereonet plots are used for formal analyses, and RQD type counts of the projected fractures are adopted for the latter analyses.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.28-41
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• 2009

We know the several construction methods for underwater tunnel, but properly submerged concrete box type tunnel was mostly good structure stability and mostly shot length of tunnels. Submerged box type tunnel was buildup the unit segments in dry dock or ship yard by 10 to 20meters. The submerged box was composed with segments was join each together. It was installing the gate and waterproofing the coupling the front hull of a box. The complete submerged box rise up to the surface water, tow in the submerged box by tugboat, going to the destination of tunnel construction site. Beforehand dredge up soil at the bottom of a underwater, sinking the submerged box, connection together complete submerged box in underwater. The research and development ILM tunneling method is receiving careful study. Biggest weakness in submerged concrete box type tunnel was pressure waterproofing, box to box connecting, complete submerged boxes navigation and installation, after operation the submerged tunnel and management concrete box structure. It was positive evidence in submerged concrete box type tunnel. We make a practical application of the principle "the ILM tunneling method in underwater construction methods."