• Proceedings of the KSR Conference
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• 2008.06a
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• pp.224-231
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• 2008

A subway or an underground railway is one of the representative public transportations which lots of people take everyday. Then, subway station, which is also one of the very important public civil infrastructures, generally services for a long period of time. During the service time of stations, they are easily damaged from environmental corrosion, material aging, fatigue, and the coupling effects with long-term loads and extreme loads. Recently, civil construction work on the places near station often creates lots of damages to the station. As these damages accumulate, the performance of station degenerates due to the above factors. They would inevitably reduce the resisting capacity of station against the disaster; even they bring into the collapse of stations with the structural failure under long-term loads and extreme loads. And, if disaster such as earthquake, fire, etc. happens, it causes huge property damage and threatens the human lives. Because of these above reasons, the structural health monitoring system need to be developed for ensuring the safety of station. In this paper, the development directions of the structural health monitoring system with fiber optic sensor and USN for subway station are briefly described.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1827-1833
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• 2008

Urban transit construction has increased since 1970, and the utilization of urban transit system also has sharply increased. However, the prediction for station scale was underestimated in design, eventually, passenger crowdedness of station, platforms and transfer pathways has got worse. Especially, safety for passenger is concerned for rush hour because of passenger crowdedness peak. Therefore, several stations, which service level is D, were investigated for passenger crowdedness. In this study, measures which are to mitigate passenger crowdedness for stations are indicated.

• Structural Engineering and Mechanics
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• v.53 no.3
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• pp.481-495
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• 2015

Many hydropower stations in southwest China are located in regions of brittle rock mass with high geo-stresses. Under these conditions deep fractured zones often occur in the sidewalls of the underground caverns of a power station. The theory and methods of fracture and damage mechanics are therefore adopted to study the phenomena. First a flexibility matrix is developed to describe initial geometric imperfections of a jointed rock mass. This model takes into account the area and orientation of the fractured surfaces of multiple joint sets, as well as spacing and density of joints. Using the assumption of the equivalent strain principle, a damage constitutive model is established based on the brittle fracture criterion. In addition the theory of fracture mechanics is applied to analyze the occurrence of secondary cracks during a cavern excavation. The failure criterion, for rock bridge coalescence and the damage evolution equation, has been derived and a new sub-program integrated into the FLAC-3D software. The model has then been applied to the stability analysis of an underground cavern group of a hydropower station in Sichuan province, China. The results of this method are compared with those obtained by using a conventional elasto-plastic model and splitting depth calculated by the splitting failure criterion proposed in a previous study. The results are also compared with the depth of the relaxation and fracture zone in the surrounding rock measured by field monitoring. The distribution of the splitting zone obtained both by the proposed model and by the field monitoring measurements are consistent to the validity of the theory developed herein.

• Journal of Environmental Science International
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• v.31 no.3
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• pp.219-226
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• 2022

This study was conducted to investigate the response of the human body to stress induced by wall recording of subway stations in the city center. The experiment was conducted as a simulation exercise, and six images were selected and produced based on Subway Line 2, a representative underground space in Seoul. The study participants included 24 male and female college students. A three-minute experiment was conducted, during which the participants were shown the control image and green wall image once each. To measure psychological status, the following measurement indicators were used: Semantic Differential, Positive Affect and Negative Affect Schedule and State-Trait Anxiety Inventory. Physiological changes were investigated by tracking participants' heart rate and blood pressure. Results showed that parasympathetic and sympathetic nerves were activated in the presence of the green wall in the subway station. The psychological evaluation analysis revealed that negative affect toward underground space decreased, while positive affect increased. This study found that the green wall in subway stations has a stable effect on the human body, both psychologically and physiologically. In the future, green walls in underground spaces can be used to reduce psychological stress and increase physiological relaxation.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.214-220
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• 2011

As the number of subway user increases, not only interests in safety increase but also interests in evacuation for a conflagration expand after 'Daegu Subway Fire Disaster' took place. It is necessary to revise the standard of evacuation time and guidelines to guarantee safety of station and platform considering changes in subway environments caused by construction of the deeply underground subway station. Hence this study investigates the current status of the evacuation time of respective station through a site investigation and the results of this study may be utilized as a basic material to calculate an appropriate evacuation time.

• International journal of advanced smart convergence
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• v.12 no.1
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• pp.208-219
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• 2023

Recently, as mega-urbanization progresses, urban logistics centered on large cities is growing rapidly, and logistics transportation is increasing due to the lack of logistics infrastructure and the operation of a delivery system using cargo trucks in the city center. being cited as a cause. In order to solve this problem, domestic researchers are conducting research on the development of " Urban Underground railway Logistics System" that minimizes the initial infrastructure construction cost by utilizing the existing urban railway facilities in the city. Therefore, this paper analyzed the usage environment of the actual urban railway station to which the system will be applied in order to derive candidates for the test bed selection of "Urban Underground railway Logistics System". The evaluation criteria for test bed candidate role selection were established, and the candidate group derived from the Brown & Gibson model was used to evaluate the candidate group and derive the candidate role. A review of the results was conducted to contribute to the establishment of a test bed for the " Urban Underground railway Logistics System" under development.

• Journal of the Korean Society for Railway
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• v.17 no.5
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• pp.328-335
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• 2014

Numerical prediction methods were applied to investigate the turbulent air currents and air-conditioning efficiency in an underground subway station, and the results compared to experimental data. The Shin-gumho Station($8^{th}$ floor underground and 43.6m in depth) in Seoul was selected for the analysis. The entire station was covered for simulation and the ventilation mode was ordinary. The ventilation diffusers were modeled as 95 square shapes of $0.6m{\times}0.6m$ in the lobby and as 222 square shapes in the platform. Cooling air of $47,316m^3/h$ was supplied and the returned air of $33,980m^3/h$ is exhausted in the lobby and the cooling air of $33,968m^3/h$ is supplied and the returned air of $76,190m^3/h$ was exhausted in the platform which is the same as the experimental data. The cases of the screen-door-closed and open were respectively investigated. A total of 7.5million grids were generated and the whole domain divided into 22 blocks for MPI efficiency of calculation. Large eddy simulation (LES) was applied to solve the momentum and energy equation.

• Journal of the Korea Concrete Institute
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• v.15 no.2
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• pp.225-233
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• 2003

Even though a lot of advanced researches on analysis, design, and performance evaluation of reinforced concrete (RC) under seismic action have been carried out, there has been only a few study on seismic analysis of underground RC structures surrounding soil medium. Since the underground RC structures interact with surrounding soil medium, a path-dependent soil model which can predict the soil response is necessary for analyzing behavior of the structure inside soil medium. The behavior of interfacial zone between the RC structure and the surrounding medium should be also considered for more accurate seismic analysis of the RC structure. In this paper, an averaged constitutive model of concrete and reinforcing bars for RC structure and path-dependent Ohsaki's model for soil are applied, and an elasto-plastic interface model having thickness is proposed for seismic analysis of underground RC structures. A finite element analysis technique is developed by applying aforementioned constitutive equations and is verified by predicting both static and dynamic behaviors of RC structures. Then, failure mechanisms of underground RC structure under seismic action are numerically derived through seismic analysis of underground RC station structure under different seismic forces. Finally, the changes of failure mode and the damage level of the structures are also analytically derived for different design cases of underground RC structures.

• Geomechanics and Engineering
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• v.5 no.2
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• pp.99-118
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• 2013

Construction of the extension project of the Bangkok MRT Blue Line underground railway was recently started in 2011. The construction of approximately 5 km long underground tunnel and 4 deep excavations of underground station are considered to be the most important geotechnical works. The pressuremeter was selected as a high-quality in situ testing of the soil to evaluate design parameters for the project. In addition, other field and laboratory tests such as vane shear and $CK_0U$ triaxial tests were included in the investigation programme. This paper aims to present the ground conditions encountered along the MRT Blue Line extension project as well as the site investigation and interpretation techniques with particular focus on the pressuremeter tests. The results are also compared with the pressuremeter investigation from the previous Bangkok MRT project.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.357-362
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• 2000

This Paper presents dynamic analysis of underground R/C Subway Structure, subjected to seismic actions. Earthquakes brought serious damage to RC subway Structure. Foe studying the collapse mechanism of underground RC Subway, seismic of a subway station is simulated in using FEM program ASP2000 of two-dimension based on the path dependent RC elastic model, soil foundation and interfacial models. The shear failure of intermediate vertical columns is founds to be the major cause of the structural collapse. According to FEM simulation of the failure mechanism, it is considered that the RC column would lose axial load carrying capacity after the occurrence of the localized diagonal shear cracks , and sudden failure of the outer frame would be followed. Specially, the shear stress in the middle slab reaches maximum shear capacity. So, the Structure would fail in the middle slab as a result of erasing the vertical ground motion computation.