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Journal of Intelligent Construction https://doi.org/10.26599/JIC.2024.9180009
Research Article | Open Access | Online first | Published: 22 February 2024

Study on critical velocity in tunnels with ceiling beams

Show Author's Information Xiangliang Tiana( ),  Linchuan Xiangb,  Shigen Fua,  Yangyang Mengc,  Huihang Chengd
Key Laboratory of Non-Coal Mine Safety Risk Monitoring and Early Warning National Mine Safety Administration, China Academy of Safety Science and Technology, Beijing 100012, China
School of Emergency Management and Safety Engineering, China University of Mining and Technology, Beijing 100083, China
Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong 999077, China
Institute of Public Safety Research, Department of Engineering Physics, Tsinghua University, Beijing 100084, China
Keywords:
heat release rate, tunnel fire, critical velocity, blocking ratio, ceiling beams
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Tian X, Xiang L, Fu S, et al. Study on critical velocity in tunnels with ceiling beams. Journal of Intelligent Construction, 2024, https://doi.org/10.26599/JIC.2024.9180009
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Abstract Full text About this article

Ceiling beams at the top of tunnels are more common in actual projects. Under the influence of thermal buoyancy, the ceiling structure significantly affects the diffusion characteristics of fire smoke within the tunnel. This study investigated the influence of ceiling structural characteristics (beam height (hB) and beam spacing (dB)) on tunnel longitudinal ventilation through numerical simulation. The results show that the spacing between tunnel ceiling beams has negligible impact on the critical velocity (V), and the determination of the critical velocity is primarily correlated with the height of the ceiling beams. Moreover, it established a dimensionless critical velocity (Vc) model for the tunnels with multiple beams in the ceiling, and this model is suitable for predicting the critical longitudinal velocity of tunnels with ceiling beams whose dimensionless beam height is less than 0.25. When the dimensionless beam height exceeds 0.25, the predictive values of this model are excessively high. This study broadens the application scope of fire smoke control models, which can offer technical support for the design of smoke prevention and exhaust systems in tunnels with similar structures.


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About this article

Study on critical velocity in tunnels with ceiling beams

Show Author's information Xiangliang Tiana( ), Linchuan Xiangb, Shigen Fua, Yangyang Mengc, Huihang Chengd
Key Laboratory of Non-Coal Mine Safety Risk Monitoring and Early Warning National Mine Safety Administration, China Academy of Safety Science and Technology, Beijing 100012, China
School of Emergency Management and Safety Engineering, China University of Mining and Technology, Beijing 100083, China
Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong 999077, China
Institute of Public Safety Research, Department of Engineering Physics, Tsinghua University, Beijing 100084, China

Abstract

Ceiling beams at the top of tunnels are more common in actual projects. Under the influence of thermal buoyancy, the ceiling structure significantly affects the diffusion characteristics of fire smoke within the tunnel. This study investigated the influence of ceiling structural characteristics (beam height (hB) and beam spacing (dB)) on tunnel longitudinal ventilation through numerical simulation. The results show that the spacing between tunnel ceiling beams has negligible impact on the critical velocity (V), and the determination of the critical velocity is primarily correlated with the height of the ceiling beams. Moreover, it established a dimensionless critical velocity (Vc) model for the tunnels with multiple beams in the ceiling, and this model is suitable for predicting the critical longitudinal velocity of tunnels with ceiling beams whose dimensionless beam height is less than 0.25. When the dimensionless beam height exceeds 0.25, the predictive values of this model are excessively high. This study broadens the application scope of fire smoke control models, which can offer technical support for the design of smoke prevention and exhaust systems in tunnels with similar structures.

Keywords: heat release rate, tunnel fire, critical velocity, blocking ratio, ceiling beams

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Publication history

Received: 20 November 2023
Revised: 11 December 2023
Accepted: 22 December 2023
Published: 22 February 2024

Copyright

© The Author(s) 2024. Published by Tsinghua University Press.

Acknowledgements

This work was supported by the National Key R&D Program of China (No. 2021YFC3001300) and the Central Fundamental Research Funds of CASST (No. 2023JBKY15).

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The articles published in this open access journal are distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

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