• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1062-1068
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• 2009

Urban construction has numerous difficulties due to ground weakness and various complaints from third party, so it is not economically efficient and constructability is not favorable. Therefore, underground, which has good ground conditions, was used for construction field and facilities such as stations, and they are scaled up to enhance accommodation of facility limitation and function of stations. Large section tunnel station construction has numerous risk factors such as work boundary of excavation equipment, a relaxation of stress concentration, a safety plan of tunnel stability, and so on. Therefore, by using large section tunnel station stability analysis considering construction step, we expect to analyze the latent problem during construction, and to stabilize a future project plan of a large section structure design by using an auxiliary method and a support design.

• The Journal of Engineering Geology
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• v.18 no.3
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• pp.339-347
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• 2008

This study was carried out to assess quantitatively the safety of a tunnel by using critical strains in the ground. Critical strain is a new material property of the ground. It can be applied as deformation limits in the ground due to excavation using the measured displacement at the tunnel construction site. To achieve this purpose, the critical strain concept was reviewed and applied to assess the tunnel safety. First of all, the calculated excavation displacements of a circular tunnel by commercial programs were investigated and inputted into a feedback analysis module to calculate strains in the ground. Then the safety of tunnels was evaluated based on the critical strain concept. Subsequently the measured displacements obtained in the field are utilized practically to assess the safety of tunnels using the critical strain concept. Through this study, it was confirmed that the critical strain concept is useful to assess the safety of tunnels quantitatively.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.717-722
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• 2010

Supersonic/Hypersonic wind tunnel is a facility which is intended to test and to observe the physical phenomena around a model by creating supersonic flow in the test section. In designing an airplane, the wind tunnel test is demanded to analyzing aerodynamic characteristics of the model without making a prototype. In this research, the model aerodynamic facility(MAF) is modified for the purpose of increasing running time and its functionality. New pneumatic valves for remote control was installed for safety requirement, and new air tanks was installed on MAF as well. A pipe system is also modified to use those new valves and tanks, and the ceiling and side glasses of the test section are switched to ones with the larger surface area. After the MAF modification, a test is performed at Mach 2, 3 and 4. In this test, shadow graph technique, one of the flow visualization methods, is used to visualize supersonic flow field. The pressure in the settling chamber and working section at Mach 2, 3 and 4 was measured in each case. As a result, the possible model size and running time are obtained.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.10a
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• pp.550-555
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• 2005

In vicinity of Seoul, there has been water service tunnel that classified into 1st grade facility by special act for the safety control of public structures and with providing capacity equals to $1,543{\times}10^3$(ton/day) and inner pressure equals to $2.5-3.5kg/cm^2$. In this research, site investigation and stability analysis for water tunnel caused by new construction of road tunnel were carried out. the ground near water tunnel were zoned into spatial area having similar geotechnical characteristics and estimating geotechnical properties for each area. The site for analysis consists of banded biotite gneiss, biotite schist and granite gneiss with spatial non-homogeneity, and for that reason weathering and fault zone were distributed with large scale. It's important thing to consider spatial ground zone and their geotechnical properties properly into stability analysis at design and construction stage. Also, using results of site investigation, stability of existing tunnel have been analyzed for Hydraulic Fracture/Jacking and deformation in detail.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1845-1850
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• 2003

The underground utility tunnels are important facility as a mainstay of country because of communication developments. The communication and electrical duct banks as well as various utility lines for urban life are installed in the underground utility tunnel systems. If a fire breaks out in this life-line tunnel, the function of the city will be discontinued and the huge damages are occurred. In order to improve the safety of life-line tunnel systems and the fire detection, the behaviors of the fire-induced smoke flow and temperature distribution are investigated. In this study we assumed that the fire is occurred at the contact or connection points of cable. Numerical calculations are carried out using different velocity of ventilation in utility tunnel. The fire source is modeled as a volumetric heat source. Three-dimensional flow and thermal characteristics in the underground tunnel are solved by means of FVM (Finite Volume Method) using SIMPLE algorithm and standard ${\kappa}-{\varepsilon}$ model for Reynolds stress terms. The numerical results of the fire-induced flow characteristics in an underground utility tunnel with different velocity of ventilation are graphically prepared and discussed.

• The Journal of Engineering Geology
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• v.17 no.2 s.52
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• pp.197-204
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• 2007

Tunnel deformation happens by excavation. After installation of support, tunnel is gradually stabilized over time. Effect of excavation on tunnel behavior decreases as increase of distance from face. If the time that the displacement converges by tunnel stabilization is estimated, processes after stabilization can be advanced and economic loss can be reduced. In this study, the distance of displacement convergent point from face in the tunnel constructed on sedimentary rock is estimated using control chart method. As the results of analysis using a control of chart, displacements in a sedimentary rock tunnel are converged within 100 m from each tunnel face.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.5
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• pp.89-95
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• 2023

The underground utility tunnel is an urban infrastructure that accommodates and manages important facilities such as water and sewage, electricity, and communication in the city, and is a national facility that needs to be protected from disasters such as fire, earthquake, and flooding. In establishing a disaster safety life cycle management system such as prediction, prevention, preparedness, response, and recovery, a disaster safety management platform for underground utility tunnel is being developed by utilizing digital twin technology in which advanced ICT technology and data are converged. In this paper, the maturity model for the disaster safety digital twin was reviewed, and the datasets necessary for implementing the digital twin at each stage were defined.

• Journal of the Korea Institute of Building Construction
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• v.20 no.3
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• pp.253-260
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• 2020

With increasing interest in an underground-type ammunition storage facility, several design results have been provided recently. However, since not only experts in the tunnel but also military persons in charge of ammunition have not fully understood the safety distance standard, reliable design results are not being produced. In this study, the effective design method of an underground-type ammunition storage facility was provided by analyzing the current safety distance standard. First, the critical safety distances that dominate the size of construction site for underground-type ammunition storage facilities were evaluated, which are the layout of chambers and the configuration of the entrances. Then, the decreasing effect of inter-chamber distance was studied according to the rock type and the storage density of ammunition. In addition, the method of designing tunnels with parallel lines and two-floors was considered for arranging more chambers while complying with the safety distance standards. In particular, numerical simulations were carried out to determine the satisfaction of the safety distance standards when an underground-type ammunition storage facility is composed of two-floor and the decreasing effect of inter-chamber distance according to the inner explosive pressure reduction. Finally, the method to adjust the size of entrances and the path of pressure were studied for decreasing the safety distance at the entrance.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.1
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• pp.33-40
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• 2016

In this study, using the Cost Prediction Model and Performance Prediction Model have developed a way to estimate future management costs and performance for bridge and tunnel by Network Level. Studies to date have primarily focused on the single facility, it is difficult to apply to the analysis of the Network Level. This study, items used as an index of 'Special Act for the Safety Control of Public Structures' was added to Usability and Functionality to Status. Action period and annual budget for each facility can be estimated through the Basic and Advanced analysis. In addition, we verified the technical feasibility through case analysis.

• Tunnel and Underground Space
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• v.27 no.4
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• pp.195-204
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• 2017

This case study introduces the construction of large cross section tunnel for underground ventilation system in Sillim-Bongcheon Tunnel Project. In order to grant the safety and efficiency in connecting the ventilation shaft (7.8 m of width, and 6.6 m of height) to a tunnel for axial fan facility (20.8 m of width, and 12.3 m of height), gradual enlargement of tunnel cross section was employed between those and temporary support method was determined based on Q system. In addition, some original designs were revised during construction stage to improve the efficiency of excavation in large cross section tunnel. The advance length was optimized and top heading of the tunnel was excavated without partition in accordance with ground condition and numerical stability analysis results. It is believed that some experiences and considerations in this case study will be useful for the future design and construction in similar large cross section tunnel such as large underground ventilation system or road tunnel with four lanes.