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A platform for research: civil engineering, architecture and urbanism
Study of tunnel fires during construction using a model scale tunnel
https://orcid.org/0000-0001-6598-9882
https://orcid.org/0000-0001-7744-2390
https://orcid.org/0000-0003-4062-5358
Highlights Characteristics of a tunnel fire during construction are studied in a model-scale tunnel. Equivalence ratio for self-extinguishment is within 0.28–1.38 for propane burner and 1.11–3.6 for fibre board with heptane. Fire in the inclined access tunnel does not self-extinguish even the ventilation rate is 0 m3/s. A recirculation of vitiated fire products is formed for a fire in the closed end of the main tunnel (excavation face). Smoke spreads over the entire cross section and the smoke spread velocity is proportional to the ventilation rate.
Abstract The paper presents a study on the characteristics of tunnel fires during construction. A model-scale tunnel was built and fire tests were conducted. The tunnel consists of an inclined access tunnel and a horizontal main tunnel. The main tunnel has two dead ends (excavation faces) and the only opening is from one side of the access tunnel. Propane gas burner and the fibre board soaked with the heptane were used as fuels. The flame characteristics, O2 and CO volume fraction and gas temperature were measured and recorded. Two typical characteristics of self-extinguishment and smoke spread were found in the tunnel fires during construction. Results indicate that when a fire occurs in the horizontal main tunnel, the critical equivalence ratio for the occurrence of self-extinguishment is within 0.28–1.38 for the propane gas burner and 1.11–3.6 for the fibre board soaked with heptane. The difference is related to the burning behavior of the different fuels used. The fire location in the horizontal tunnel also has a significant influence on the fire development. A well-ventilated fire at the center of the horizontal tunnel becomes under-ventilated due to vitiation when it is located at the closed end of the horizontal tunnel. Besides, when a fire occurs at the closed end of the horizontal main tunnel, the stratification of smoke is destroyed after hitting the closed end, and then the smoke seems to spread over the entire cross section of the tunnel. The smoke spread velocity is found to be proportional to the ventilation rate. However, when a fire occurs at the closed end of the inclined access tunnel (lower end), the fire does not self-extinguish, even when the ventilation rate is 0 m3/s. The corresponding smoke spread velocity is higher than that in the horizontal main tunnel. The outcomes of this study provide new experimental information that contributes to improve the understanding of characteristics of tunnel fires during construction and can help firefighters to make better decisions during the rescue processes.
Study of tunnel fires during construction using a model scale tunnel
https://orcid.org/0000-0001-6598-9882
https://orcid.org/0000-0001-7744-2390
https://orcid.org/0000-0003-4062-5358
Highlights Characteristics of a tunnel fire during construction are studied in a model-scale tunnel. Equivalence ratio for self-extinguishment is within 0.28–1.38 for propane burner and 1.11–3.6 for fibre board with heptane. Fire in the inclined access tunnel does not self-extinguish even the ventilation rate is 0 m3/s. A recirculation of vitiated fire products is formed for a fire in the closed end of the main tunnel (excavation face). Smoke spreads over the entire cross section and the smoke spread velocity is proportional to the ventilation rate.
Abstract The paper presents a study on the characteristics of tunnel fires during construction. A model-scale tunnel was built and fire tests were conducted. The tunnel consists of an inclined access tunnel and a horizontal main tunnel. The main tunnel has two dead ends (excavation faces) and the only opening is from one side of the access tunnel. Propane gas burner and the fibre board soaked with the heptane were used as fuels. The flame characteristics, O2 and CO volume fraction and gas temperature were measured and recorded. Two typical characteristics of self-extinguishment and smoke spread were found in the tunnel fires during construction. Results indicate that when a fire occurs in the horizontal main tunnel, the critical equivalence ratio for the occurrence of self-extinguishment is within 0.28–1.38 for the propane gas burner and 1.11–3.6 for the fibre board soaked with heptane. The difference is related to the burning behavior of the different fuels used. The fire location in the horizontal tunnel also has a significant influence on the fire development. A well-ventilated fire at the center of the horizontal tunnel becomes under-ventilated due to vitiation when it is located at the closed end of the horizontal tunnel. Besides, when a fire occurs at the closed end of the horizontal main tunnel, the stratification of smoke is destroyed after hitting the closed end, and then the smoke seems to spread over the entire cross section of the tunnel. The smoke spread velocity is found to be proportional to the ventilation rate. However, when a fire occurs at the closed end of the inclined access tunnel (lower end), the fire does not self-extinguish, even when the ventilation rate is 0 m3/s. The corresponding smoke spread velocity is higher than that in the horizontal main tunnel. The outcomes of this study provide new experimental information that contributes to improve the understanding of characteristics of tunnel fires during construction and can help firefighters to make better decisions during the rescue processes.
Study of tunnel fires during construction using a model scale tunnel
https://orcid.org/0000-0001-6598-9882
https://orcid.org/0000-0001-7744-2390
https://orcid.org/0000-0003-4062-5358
Highlights Characteristics of a tunnel fire during construction are studied in a model-scale tunnel. Equivalence ratio for self-extinguishment is within 0.28–1.38 for propane burner and 1.11–3.6 for fibre board with heptane. Fire in the inclined access tunnel does not self-extinguish even the ventilation rate is 0 m3/s. A recirculation of vitiated fire products is formed for a fire in the closed end of the main tunnel (excavation face). Smoke spreads over the entire cross section and the smoke spread velocity is proportional to the ventilation rate.
Abstract The paper presents a study on the characteristics of tunnel fires during construction. A model-scale tunnel was built and fire tests were conducted. The tunnel consists of an inclined access tunnel and a horizontal main tunnel. The main tunnel has two dead ends (excavation faces) and the only opening is from one side of the access tunnel. Propane gas burner and the fibre board soaked with the heptane were used as fuels. The flame characteristics, O2 and CO volume fraction and gas temperature were measured and recorded. Two typical characteristics of self-extinguishment and smoke spread were found in the tunnel fires during construction. Results indicate that when a fire occurs in the horizontal main tunnel, the critical equivalence ratio for the occurrence of self-extinguishment is within 0.28–1.38 for the propane gas burner and 1.11–3.6 for the fibre board soaked with heptane. The difference is related to the burning behavior of the different fuels used. The fire location in the horizontal tunnel also has a significant influence on the fire development. A well-ventilated fire at the center of the horizontal tunnel becomes under-ventilated due to vitiation when it is located at the closed end of the horizontal tunnel. Besides, when a fire occurs at the closed end of the horizontal main tunnel, the stratification of smoke is destroyed after hitting the closed end, and then the smoke seems to spread over the entire cross section of the tunnel. The smoke spread velocity is found to be proportional to the ventilation rate. However, when a fire occurs at the closed end of the inclined access tunnel (lower end), the fire does not self-extinguish, even when the ventilation rate is 0 m3/s. The corresponding smoke spread velocity is higher than that in the horizontal main tunnel. The outcomes of this study provide new experimental information that contributes to improve the understanding of characteristics of tunnel fires during construction and can help firefighters to make better decisions during the rescue processes.
Study of tunnel fires during construction using a model scale tunnel
Yao, Yongzheng (author) / Li, Ying Zhen (author) / Lönnermark, Anders (author) / Ingason, Haukur (author) / Cheng, Xudong (author)
Tunnelling and Underground Space Technology ; 89 ; 50-67
2019-03-20
18 pages
Article (Journal)
Electronic Resource
English
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