• Journal of Korean Tunnelling and Underground Space Association
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• v.14 no.6
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• pp.561-573
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• 2012

Recently, tunnel constructions have been increased in Korea. According to the increment of tunnel constructions, cases of tunnel collapses also have been increased under tunnel construction. Among these tunnel collapses, after a certain amount of time has elapsed due to excessive displacements on slope of tunnel exit or entrance, cases of tunnel collapse have been increased rapidly. Therefore, the case study was conducted in this study to figure out factors effect on the tunnel collapses due to excessive displacements on tunnel exit or entrance slopes. Base on the case study, the fragmental zone of fault and the rainfall were most important factors on the collapse.

• Journal of Korean Tunnelling and Underground Space Association
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• v.3 no.4
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• pp.25-34
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• 2001

As the topography of Korea consists of mountains at about seventy percent, there is necessarily an increasing demand for tunnel construction according to the expansion of the existing highway and construction of new highway. The concrete lining of tunnel portals has been designed with reinforced concrete to resist the cracking due to the difference in temperature in the inside and outside of tunnel. In the paper, the application of steel fiber reinforcement concrete was analyzed as the lining concrete at tunnel portals and through structure analysis and field model test the suitability of the steel fiber reinforcement concrete was assessed as the lining member of tunnel portal.

• Tunnel and Underground Space
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• v.11 no.1
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• pp.20-29
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• 2001

Final convergence of tunnel crown due to excavation have been well predicted by regression analysis which is expressed as a function of convergence curve on a time and distance dependent. In this study, the validity of the equations for shallow, wide tunnel was investigated by measurement and numerical analysis. Studied tunnel(Sansoo Tunnel) is located at the boundary of downtown and mountain park. Exponential predictions equation was better coincided with measured data than fractional equation for studied tunnel, although the ground was expected to be elasto-plastic. This is because weathered rock ground is changed elasto-plastic ground into elastic ground by multi-steel grouting and forepoling.

• Explosives and Blasting
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• v.14 no.2
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• pp.71-80
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• 1996

A series of nurmerical analysse for the earhtquake of Iran railway tunnles under construction by NATM(New Astrian Tunnelling Method) were careid out throuth a pseudo-dynamic analyses techique used in a FFM computer program, DWTAP(Daewoo Tunnel Analysis Program), and the results are described in the paper. The analyses were performErl for two case;one is for the primary supports and the other is for the rompletEd permanent roncrete lining. The horizontal and verical groW1d accelerations for the design were estimatEd as 0.34 g and 0.23 g, respectively based on the historical reismic rerords in the proj3et area and the empirical equations. The results show that the turmel would be safe W1der the anticipitOO earthquake motion with the permanent roncrete lining, but some minor cracks rnigt be developErl in the primary shotcrete lining without any significant structural damages.

• Tunnel and Underground Space
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• v.19 no.3
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• pp.226-235
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• 2009

Force induced by the natural ventilation in tunnel is likely to generate adverse influences on the airflow during the normal operation and create even more unfavorable circumstances during the tunnel fire. The influence of the natural ventilation is required to take into account in designing and operating the ventilation as well as safety systems. The magnitude of natural ventilation force depends on a variety of factors associated with the topographical, meteorological and physical features of tunnel. Unfortunately, at this moment those are difficult to quantify and none of the countries has suggested its estimation method in the design guideline. This study aims at quantifying the natural ventilation force at a local highway tunnel by three different methods. The first method employes direct measurement of the pressure at portals, while the second applies a stepwise approach to eliminate the piston effect ahead of deriving the natural ventilation force and the third method uses the concept of barometric barrier.

• Economic and Environmental Geology
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• v.53 no.2
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• pp.133-145
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• 2020

Soil in mine waste-rock fields, and at the pithead, sediments and farmlands around an abandoned mine in the Chungcheong Province of South Korea were investigated to assess the distribution of metallic elements and to understand the scope of the pollution. Reddening was observed from the mine up to a distance of 61 m. Losses of waste rock around the mine were assessed over a section of 1800 ㎥. Yellowish precipitates on the bottom of a stream were identified as ferrihydrite and goethite. For anions, a mean sulfate ion level over 773.6 mg/L was found during August in the river water samples. Mine drainage at the site was shown to have a pH of 4.9 and a sulfate concentration of 1557.8 mg/L during the August rainy season. A possible cause of the metallic element contamination in the mine is waste-rock loss, because mine waste-rock is located on the slope in this area. In conclusion, the total soil area to be treated, based on the amount that exceeded the recommended Korean soil pollution levels, was assessed to be 10,297 ㎡.

• Journal of Korean Tunnelling and Underground Space Association
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• v.7 no.3
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• pp.259-267
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• 2005

This paper analyzed characteristic of temperature change as well as bottom of tunnel with thermometer according to tunnel length and region during one year. And it measured temperature distribution near tunnel portal. In the paper it was known that tunnel entrance and exit have different characteristic temperature distribution in accordiance with bottom of tunnel per tunnel length. Temperature of tunnel changed from tunnel exit to fifty meter and distribution of tunnel temperature was established uniform regardless of tunnel length. But temperature distribution of tunnel changed in tunnel entrance differ from tunnel exit in the location of one hundred twenty five meter and one hundred fifty meter. Cold air inflowed from tunnel entrance have influenced with the location of one hundred twenty five meter and one hundred fifty meter.

• Journal of Korean Tunnelling and Underground Space Association
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• v.15 no.1
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• pp.33-47
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• 2013

When a bomb explodes near a tunnel, generated muck should be quickly moved outside for rehabilitation of the tunnel. In this study, the amount of muck generated by an explosion was estimated and a methodology was presented for the prediction of the muck hauling time. To this end, 3D-meshes were made by using SoildWorks and blasting analyses were performed by using AUTODYN. A method was suggested to calculate theoretically the amount of muck which inflows into a tunnel based on the relationship between the tunnel and the fragmentation zone obtained from the analysis results. Also, muck hauling times were predicted based on the selection of construction equipment and the results were compared and analyzed. As a result, it was convinced that the amount of muck flowing into the tunnel could be effectively calculated by classifying the relationship between a tunnel and the fragmentation zone into 4 cases and using the mensuration by parts. Also it was confirmed that the closer blasting location is to the portal and the excavation surface of a tunnel, and the more blasting location deviates from the center line of the tunnel, the lesser amount of muck occurs and thus the muck hauling time decreases as well.

• Journal of Korean Tunnelling and Underground Space Association
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• v.5 no.2
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• pp.115-134
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• 2003

Recently, there are many cases in the roadway design for successive tunnel with small distance between two tunnels. In this case, the degree of interference for successive tunnels is a significant consideration in the design of ventilation systems. Also, Re-inflows of contaminated air in successive tunnel make serious ventilation problems in case of fire accident in the tunnel. In this study, for successive tunnels in Donghae highway project, the concentration of contaminant such as CO, NOx and Smoke were calculated by numerical analysis using 1D and 3D-CFD analysis. And, the rate of re-inflow at the portals of successive tunnel according to the direction of wind were analysed.

• The Journal of Engineering Geology
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• v.20 no.1
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• pp.71-78
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• 2010

The Gagok mine is a contact metasomatic deposit, located at Gagok-myeon, Samcheok city and Cheoram-dong, Taebaek city, Gangwon province. The deposit lies within the limestone of Myobong and Pungchon formations, and exists the contact of intrusive granite porphyry. In order to determine the direction and extension of mineralization in the gallery and around the entrance of the ore deposit, we used the ground magnetic survey, the direct current (dc) resistivity survey using dipole-dipole array, and resistivity tomography survey. The ground magnetic survey did not detect the anomalous zone due to ore deposit, while the dc resistivity survey and resistivity tomography survey were successful in delineating the anomalous zone related to the extension of fault toward $N50^{\circ}W$.