• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.9 no.9
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• pp.721-736
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• 2019

In this paper, the behavior of the fire smoke due to the operation of the ventilation systems when the fire occurred in the underground station (6 basement floors) and the tunnel at the great depth was measured. Fire smoke was generated by using a smoke generator which realized heat buoyancy effect by using hot air blower. The two locations of the fire were selected on the platform and on the platform of the tunnel located outside the screen door. A ventilation mode is generally used in which smoke is exhausted through a vent hole provided in a platform when a platform fire occurs. The tests were performed by operating the exhaust through the ventilation holes of the tunnel part located at both ends of the platform. The smoke density and the wind speed/velocity were measured at various positions, and the videos were taken to analyze the movement and smoke of the smoke. In both cases for fire inside the platform and in the railway tunnel, due to the ventilation mode operation of the fan for the platform and the exhaust of the fans in the tunnel smoke were well exhausted and the smoke propagation to the area near the smoke zone was suppressed. The smoke-control mode, which is applied to both fans for the platform and fans for in the tunnel at both ends of the platform, can provide a safer evacuation environment to the passengers from the fire smoke when the platform fire or fire train stops.

• Journal of Korean Tunnelling and Underground Space Association
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• v.22 no.2
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• pp.171-183
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• 2020

The purpose of this study is to analyze in advance the problems and improvements that may occur during the construction of intermediate slabs and the loading of intermediate slabs through the preliminary structural safety evaluation of intermediate slabs for Test bed structures in deep depth tunnels. The Test bed construction can verify and confirm the results of the design and construction technology development of large depth double deck tunnel through the process, and can also be used as a learning site for engineers and the general public to speed up the time of underground space development. There will be an opportunity to do this. In particular, the design load of middle slab built inside the circular deep-depth double-sided tunnel cross-section varies depending on the construction method and the construction equipment load used. Class 3 truck load of KL-510 assumed to be common load to upper and middle slab during loading and installation is loaded on upper and lower slab with different working position for each load combination Analyzed.

• Tunnel and Underground Space
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• v.33 no.6
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• pp.561-573
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• 2023

Korea Atomic Energy Research Institute (KAERI) constructed the KURT (KAERI Underground Research Tunnel) to analyze the hydrogeological/geochemical characteristics of deep rock mass. Numerous boreholes have been drilled to conduct various field tests. The selection of suitable investigation intervals within a borehole is of great importance. When objectives are centered around hydraulic flow and groundwater sampling, intervals with sufficient groundwater flow are the most suitable. This study defines such points as hydraulic outliers and aimed to detect them using borehole geophysical logging data (temperature and EC) from a 1 km depth borehole. For systematic and efficient outlier detection, machine learning algorithms, such as DBSCAN, OCSVM, kNN, and isolation forest, were applied and their applicability was assessed. Following data preprocessing and algorithm optimization, the four algorithms detected 55, 12, 52, and 68 outliers, respectively. Though this study confirms applicability of the machine learning algorithms, it is suggested that further verification and supplements are desirable since the input data were relatively limited.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.7 no.4
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• pp.243-253
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• 2009

In this study, research status on radionuclide and colloid migration in underground research facilities including KURT (KAERI Underground Research Tunnel) was investigated. Some foreign underground research facilities constructed in crystalline rock formations such as granite were briefly introduced and compared. International joint researches concerned with the radionuclide and colloid migration were investigated particularly for the Grimsel Test Site (GTS) and $\ddot{A}$sp$\ddot{o}$ Hard Rock Laboratory by analyzing major research items, on-going research projects, and future plans.

• Journal of Korean Tunnelling and Underground Space Association
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• v.12 no.6
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• pp.417-427
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• 2010

In the ease that a new cross tunnel is constructed under the existing tunnel, development of a longitudinal arching would be influenced by the existing tunnel. But it is not enough to investigate. Especially, the influence of the structure loads on the ground surface on the new tunnel, which the under-passes existing tunnel has been rarely studied. This study, therefore, aimed to clarify the effect of the existing tunnel and the structure on the ground surface on the development of a longitudinal ground arching during the excavation of a cross tunnel under the existing tunnel. Two-dimensional model tests were carried out in the test box, whose dimension was 30 cm (wide) ${\times}$ 113 cm (deep) ${\times}$ 87 cm (high). The existing tunnel was made of S21 steel tube in 16 cm diameter and 1 mm thickness. The ground surface load was 4.9 kPa and was loaded on the model structure in the size with 30 cm width ${\times}$ 16 cm height. New tunnel was excavated in 250 mm height by a bench cut method. As results, the longitudinal arching would be developed but it was severely influenced by not only the existing upper tunnel but also the ground surface load. The influence of the ground surface load on the development of longitudinal ground arching around a new tunnel showed the highest value when the tunnel face located direct under the surface load.

• Tunnel and Underground Space
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• v.34 no.2
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• pp.169-184
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• 2024

This study investigates acoustic emission (AE) and micro-deformation characteristics of circular openings through biaxial compression experiments. The experimental results showed a significant increase in the frequency, count, energy, and amplitude of AE signals immediately before damage occurred in the circular opening. The differences in frequency and count between before and after damage initiation were significantly pronounced, indicating suitable factors for identifying damage occurrence in circular openings. The results for digital image correlation (DIC) technique revealed that micro-deformation was concentrated around the openings, as evidenced by the spatial distribution of strain. In addition, spalling was observed at the end of the experiments. The AE and micro-deformation characteristics presented in this study are expected to serve as fundamental data for evaluating the stability of underground openings and boreholes for deep subsurface projects.

• Tunnel and Underground Space
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• v.19 no.4
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• pp.355-365
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• 2009

This paper proposes an elasto-plastic finite difference method which is useful for the stability evaluation of concrete lining installed in a deep circular tunnel. Mohr-Coulomb criterion is assumed for the condition of yielding in both the rock mass and concrete lining. In order to take into account the installation delay of lining after the excavation, the outer boundary pressure acting on the lining was calculated with the consideration of the convergence occurred before the lining installation. The distributions of stress and displacement in the rock mass and lining were calculated based on the method proposed Lee & Pietruszczak (2008). The applicability of the proposed method was demonstrated by conducting the elasto-plastic analysis of concrete lining supporting an imaginary compressed air storage tunnel. The analysis result revealed that the exact determination of the boundary pressures acting on the concrete lining is of importance in the stability analysis of concrete lining.

• Tunnel and Underground Space
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• v.7 no.1
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• pp.39-50
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• 1997

Reference concepts for the disposal of spent nuclear fuel and the current status of underground rock laboratory were studied. An analysis to simulate the deep disposal of spent nuclear fuel in saturated rock mass was conducted. Main input parameters for numerical study were determined based on the KBS-3 concept. A series of results showed that the temperature distribution around a cavern reached the maximum value at about 10 years after the emplacement of spent fuel. The maximum temperature at the surface of canister was more than about 12$0^{\circ}C$ at about 4 years. This temperature was not much higher than the temperature criteria to meet the performance criteria of an artificial barrier in the KBS-3 concept. The maximum upward displacement due to the heat generation of spent fuel was about 0.9cm at about 10 years after the emplacement of spent fuel. It turned out that the vertical displacement became smaller with the decrease in heat generation of a canister. The quantity of groundwater inflow into a disposal tunnel increased by about 1.6 times at 20 years after the emplacement of spent fuel with the increase of pore pressure around a cavern.

• Tunnel and Underground Space
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• v.10 no.4
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• pp.544-552
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• 2000

Norway has the geological of condition of hard bedrocks, high mountains, deep valleys and fjords. In this background many tunnels and rock caverns are developed. In this process of constructing tunnels and rock caverns Norway seems to have strong competitiveness in the construction of tunnels. In spite of high salaries to the tunnel workers, Norwegian contractors are probably producing the cheapest tunnels and rock caverns in the world. Besides benefit of hard-rock geology, Norwegian cost-saying is owing to the Norwegian excavation technique in hard rocks such as unlined pressure tunnels, air cushion chambers, underwater piercing, and reasonable contract system and organization of workers developed from the accumulated experience. Brief analytical description of them are given in this paper in order to stimulate the utilization of the underground spaces.

• Journal of Korean Tunnelling and Underground Space Association
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• v.12 no.1
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• pp.87-94
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• 2010

This study mainly focused on the subsurface settlement due to shallow and deep tunneling in sandy ground. In order to figure out theoretical deformation patterns in association with the ground loss during the progress of tunneling, laboratory model tests using aluminum rods and finite element analyses using the CRISP program were carried out. As a result of comparison between the model test and the finite element analysis, the similar deformation patterns were found. In addition, it was identified that the most K values obtained from both the FEA and the model tests were distributed between Dyer et al. (1996) and Moh et al. (1996) of the field observation data. Based on the model test data, the linear equation of K for the sandy soil could be obtained.