Numerical study of the characteristics of smoke spread in tunnel fires during construction and method for improvement of smoke control

Yao, Yongzheng; Wang, Rui; Xia, Ziyang; Ren, Fei; Zhao, Jinlong; Zhu, Hongqing

doi:10.1016/j.csite.2022.102043

Cited by 22 publications

(7 citation statements)

References 20 publications

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“…Meng et al [18] studied the characteristics of tunnel fires and the variation in smoke back-layering length through model experiments, considering different heat release rates, combustion interval distances and ventilation speeds. Yao et al [19,20] investigated the characteristics of smoke movement and control in a longitudinal ventilation tunnel fire by considering different heat release rates, fire locations, longitudinal wind speeds and transverse channel intervals. Chow et al [21] studied the smoke movement law of inclined tunnel fires under longitudinal ventilation conditions and proposed a modified empirical formula for the critical velocity of inclined tunnels.…”

Section: Introductionmentioning

confidence: 99%

Study on the Effect of Natural Wind on the Smoke Spread Law of Extra-Long Tunnel Fires with Inclined Shafts for Air Supply and Exhaust

Tan,

Wang,

Zhang

et al. 2024

Buildings

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High-temperature smoke generated by tunnel fires is the most important factor causing casualties. To explore the influence of natural wind on fire smoke movement in an extra-long highway tunnel based on the Taihang Mountain Tunnel, the distribution law of natural wind in the tunnel was obtained by on-site monitoring of the meteorological conditions at the tunnel site. A three-dimensional fire dynamics tunnel model considering an inclined shaft smoke exhaust was established, and the influence of natural wind on tunnel temperature distribution, smoke spread and smoke exhaust efficiency was studied. The results show that the natural wind speed of the Taihang Mountain Tunnel is mainly concentrated at 0~3 m/s. The main wind direction of the natural wind on the left tunnel is opposite to the driving direction, and the distribution probability of the main wind direction in each section is 81.27% and 72.15%, respectively. The main wind direction of the right tunnel is the same as the driving direction, and the distribution probability of the main wind direction in each section is 56.78%, 69.73%, 67.32% and 64.65%, respectively. The negative natural wind can inhibit the smoke spread downstream of the smoke exhaust port, but it is not conducive to the smoke exhaust. The positive natural wind promotes the smoke spread to the downstream of the smoke exhaust port, and the larger the natural wind speed, the longer the spread length. Natural wind reduces the smoke exhaust efficiency. For positive or negative natural wind with a guaranteed rate of 70%, the smoke exhaust efficiency is reduced by 27.76% and 15.59%, respectively, compared with the condition without natural wind. The research results can provide a useful reference for the design of fire smoke exhausts and smoke control schemes in extra-long highway tunnels.

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Section: Introductionmentioning

confidence: 99%

Study on the Effect of Natural Wind on the Smoke Spread Law of Extra-Long Tunnel Fires with Inclined Shafts for Air Supply and Exhaust

Tan,

Wang,

Zhang

et al. 2024

Buildings

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“…The extra-long road tunnel itself is a long, narrow, and nearly enclosed structure [6]. The smoke from the fire is difficult to vent and spreads over a long distance in the tunnel [7]. The smoke contains a large amount of CO and other toxic gases, which can lead to death by poisoning or asphyxiation if large amounts of smoke accumulate in the travel space [8].…”

Section: Introductionmentioning

confidence: 99%

A Study on the Evacuation of an Extra-Long Highway Tunnel Fire—A Case Study of Chengkai Tunnel

Wang

Chen

et al. 2023

Sustainability

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The smoke from tunnel fires spreads over long distances and is difficult to vent. Smoke accumulation leads to high temperatures, low visibility, and high concentrations of toxic gases, which greatly hinders the evacuation of people inside the tunnel. In this paper, a representative extra-long highway tunnel—Chengkai Tunnel—is selected as the engineering background, and a tunnel model is built using FDS and Pathfinder software to simulate the fire scenario and evacuation scenario under different longitudinal wind speeds. The concept of safe evacuation reliability is proposed to describe the relationship between the ASET (available safe egress time) and the RSET (required safe egress time). The simulation results show that with the increase in longitudinal wind speed, the ASET upstream of fire source increases first and then remains unchanged, while ASET downstream of fire source increases first and then decreases. The ASET upstream of the fire source is affected by visibility, while the ASET downstream of the fire source is affected by visibility when the wind speed is low, and is affected by temperature as the wind speed increases. The bottleneck effect is an important reason for the long evacuation time of people. The blockage time is a power function of the evacuation movement time, and increasing the width of the cross passage can improve the evacuation efficiency of the tunnel. The increase in the number of evacuees will reduce the reliability of the safe evacuation of personnel. Among all simulated scenarios, a longitudinal wind speed of 2.5 m/s has the highest safe evacuation reliability, with 0.79, 0.92, and 0.99 for scenarios R1, R2, and R3, respectively. Excessive wind speed reduces the safe evacuation reliability downstream of the fire source.

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“…According to statistics from the International Tunneling and the Underground Space Association (ITA), in recent years, the tunnels under construction in China account for about 50% of the world's total tunnels under construction. The rapid development of tunnel construction has also brought significant fire safety hazards [3][4][5]. Ventilation and smoke extraction facilities in tunnels under construction cannot be set according to the requirements of the completed operating tunnel, and in the event of a fire, smoke is very difficult to control; the consequences of this are likely very serious.…”

Section: Introductionmentioning

confidence: 99%

“…In the second scenario, one end of the tunnel under construction is the working face, and the other end is connected to the outside. For fire and smoke control and personnel evacuation in tunnels under construction, Yao et al [11] proposed a simple improvement method for controlling smoke from fires in tunnels under construction, wherein a drainage device is placed in the middle of the construction passageway to divide the access for both natural ventilation and smoke exhaust, after which the temperature rise in the tunnel decreases significantly and the mass flow rate of the smoke through the construction passageway increases. Yuan et al [12] invented a fire smoke control device for a single exit tunnel under construction by fully Compared with an operating tunnel with openings at both ends, the structure of a tunnel under construction is more confined.…”

Section: Introductionmentioning

confidence: 99%

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Smoke Movement and Control in Tunnels under Construction: Recent Research Progress and Future Directions

Yao

Xia

Wang

et al. 2023

Fire

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Numerical study of the characteristics of smoke spread in tunnel fires during construction and method for improvement of smoke control

Cited by 22 publications

References 20 publications

Study on the Effect of Natural Wind on the Smoke Spread Law of Extra-Long Tunnel Fires with Inclined Shafts for Air Supply and Exhaust

Study on the Effect of Natural Wind on the Smoke Spread Law of Extra-Long Tunnel Fires with Inclined Shafts for Air Supply and Exhaust

A Study on the Evacuation of an Extra-Long Highway Tunnel Fire—A Case Study of Chengkai Tunnel

Smoke Movement and Control in Tunnels under Construction: Recent Research Progress and Future Directions

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