• Journal of Korean Tunnelling and Underground Space Association
• /
• v.16 no.1
• /
• pp.105-115
• /
• 2014

A numerical analysis on the smoke behavior and evacuee safety has been performed with computational fluid dynamics. The purpose of this study is to build computational processes for an evacuation and prevention of a fire disaster of a 3 km-length tunnel in Korea. To save computational cost, 1.5 km of the tunnel that can include a few cross-passing tunnels is considered. We are going to assess the fire safety in a road tunnel according to the smoke level, which consists of the smoke density and the height from the floor. The smoke density is obtained in detail from three-dimensional unsteady CFD analysis. To obtain proper temperature distributions on the tunnel wall, one-dimensional conduction equation is considered instead of an adiabatic wall boundary or a constant heat flux. The tunnel considered in this study equips the cross passing tunnels for evacuees every 250 m. The distance is critical in both safety and economy. The more cross passing tunnels, the more safe but the more expensive. Three different jet fan operations can be considered in this study; under- and over-critical velocities for normal traffic condition and 0-velocoty operation for the traffic congestion. The SE (smoke environment) level maps show a smoke environment and an evacuating behavior every moment.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.6 no.1
• /
• pp.51-59
• /
• 2004

The effectiveness of one dimensional critical velocity method for evacuation environment at 10MW fire size in a railroad tunnel have been investigated in this paper by three dimensional CFD method. It was performed to evaluate the evacuation environment in terms of temperature distribution, visible distance distribution and CO concentration at some tunnel inlet velocity, 1m/s, 2m/s (near critical velocity), and 3m/s. At all inlet velocity, passenger should give away downward the flow direction because the inlet velocity can not afford to sufficient evacuation environment for passengers. In case of 3m/s inlet velocity, however, the evacuation environment for passengers is better than the other cases. To provide more safe evacuation environment on fire situation, tunnel inlet velocity should be larger than critical velocity.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
• /
• 2012.04a
• /
• pp.428-431
• /
• 2012

본 연구에서는 터널 화재 시 보다나은 대피 안전성확보를 위해 2차적 사고예방에 목적을 둔 정보표지판(Variable Message Sign)을 제연막으로 활용함으로써 터널 대피자의 안전성을 확보하고 대피취약자로 하여금 충분한 대피시간의 확보를 위한 최적의 조건을 제시하고자 하였다. 정보표지판의 다양한 설치 조건에 따라 화재연기가 전파되어지는 거리를 화재 시뮬레이션인 FLUENT와 피난 시뮬레이션인 SIMULEX를 이용하여 통근자와 고령자의 안전거리를 비교하고 대피 안전성을 검토하였다.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.17 no.3
• /
• pp.215-226
• /
• 2015

In this study, with variables the cross section area ($97m^2$, $58m^2$, $38m^2$) and the wind velocity(0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5 m/s), the time of getting off train dependent on the way of itself and the width of the evacuation route was analyzed, and also fire and evacuation characteristics is reviewed by cross section area of each wind velocity. As the result, if cross section become smaller, the density of harmful gases in the tunnel increased more than the ratio of decreasing cross section area. In the case of small cross sectional area, the surrounding environment from initial fire is indicated to exceed the limit criteria suggested in performance based design. In the analysis of effective evacuation time for evacuation characteristics, the effective evacuation time was the shortest in the case of evaluating effective evacuation time by the visibility. Also, there was significant difference between the effective evacuation time on the basis of performance based evaluation and the effective evacuation time obtained by analyzing FED (Fractional effective dose), one of the analysis method obtaining the point that deaths occur, against harmful gases.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.35 no.5
• /
• pp.1157-1163
• /
• 2015

The purpose of this study is to reveal the effects of the number of users and their spatial distribution on the evacuation time in a road tunnel in the event of a fire. An agent-based evacuation model was implemented using Netlogo following the ODD protocol. The proposed model illustrates how the evacuation behavior of one can hinder others across different evacuation environments. Simulations show that evacuation time increases with the number of users when they are randomly located in a road tunnel.

• Tunnel and Underground Space
• /
• v.15 no.6 s.59
• /
• pp.452-461
• /
• 2005

In a bidirectional tunnel, the accident rate is 1.5 times as high as that of one directional tunnel , the risk of a fire is increased. On fire, there is a problem that the jet fan should not be operated until completion of refuge. To be special, as the great damages occur owing to the expansion of smoke in long tunnels, there is a need to minimize fatality by constructing cross passage and smoke removal system. This study aims at verifying the efficiency of smoke exhaust system through fire propagation simulation as well as scale model test. The results show that completion of escape through emergency exit requires 335 seconds, while addition of smoke exhaust system reduce the escape time to 185 seconds. Also, near the fire source temperature decreased by about $60^{\circ}C$. Without the exhaust system, fire propagation speed was in the range of 0.36 and 0.82 m/s, and it dropped to $0.27\~0.58\;m/s$ with the exhaust system on. Taking into account the escape speed of tunnel users, usually $0.7\~1.0\;m/s$, the emergency exit built every 150m is sufficient for the safe egress. The ultimate goal of this study is to provide fundamental information for the smoke exhaust system in bidirectional tunnels.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.7
• /
• pp.535-546
• /
• 2019

The purpose of this research was to analyze the relationship between human risk factors and evacuation behavior stages for tunnel safety. Therefore, we conducted a survey using a structured questionnaire on the relationship between safety facilities and safety behavior in order to derive an optimized interaction between the two. The research subjects were 141 tunnel users who understand the tunnel environment. The survey period was from June 24, 2018, to September 28, 2018. As data analysis methods, we employed a frequency analysis, a multiple regression analysis, and an independent-sample t-test. In the analysis of the correlation between the human risk factors and the major variables of evacuation behavior, the evacuation phases 1, 2, and 3 were all correlated with acceleration and delay, and the human risk factors were partially correlated. In the multiple regression analysis, the will to comply with laws (${\beta}=0.188$, p=0.034) and information recognition within the tunnel (${\beta}=0.220$, p=0.009) were factors that influence the relationship between human risk factors and evacuation behavior, indicating 12% explanatory power of the impact of human risk factors for the acceleration of evacuation behavior 3. The important variables between human risk factors and evacuation behavior were compliance with laws and information recognition in tunnels. Hence, it is necessary to study the elements that interact with the environment in the tunnel.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.17 no.2
• /
• pp.117-125
• /
• 2015

Quantitative risk assessment (QRA) of railway is to create a variety of scenario and to quantify the degree of risk by a result of the product of accident frequency and accident. Quantitative risk Assessment is affected by various factors such as tunnel specifications, characteristics of the fire, and relation of smoke control and evacuation direction. So in this study, it is conducted that how the way of smoke control and the relation of smoke control and evacuation direction affect quantitative risk assessment with variables (the tunnel length (2, 3, 4, 5, 6 km) and the slope (5, 15, 25‰)). As the result, in a train fire at the double track tunnel (Area = $97m^2$), it is most efficient to evacuate to the opposite direction of smoke control regardless of the location of train in train fire. In addition, under the same condition, index risk in mechanical ventilation up to 1/10.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.22 no.4
• /
• pp.401-417
• /
• 2020

As an increasing demand for rapid railway transportation, the construction of sidetrack is inevitable to operate local and express trains simultaneously. However, the current technologies for the sidetrack construction method require a long construction period by interrupting the operation of the existing subway line, as well as cause a huge economic loss. Thus, it is necessary to study the sidetrack construction method under the special situation that the subway is in operation and to analyze the risk of the existing tunnel enlargement process for the sidetrack construction. Therefore, in this paper, the Government Complex Gwacheon station on Subway Line 4 was considered as a target station for the virtual sidetrack construction and the optimal sidetrack construction plan was derived. Subsequently, the application of risk management process was carried out in the order of identifying risk, risk response planning, performing a risk analysis, risk monitoring and control for potential risk events during the construction of sidetrack under the subway operation. A total of eight potential risk events and risk mitigation methods were selected, and a risk assessment matrix was established using the five-step risk probability and impact level criteria to perform the risk assessment including residual risks. Based on the results of the risk assessment, the risk grade and the reduction effect of each risk mitigation method were confirmed.

• Magazine of korean Tunnelling and Underground Space Association
• /
• v.19 no.2
• /
• pp.23-29
• /
• 2017