Study of tunnel fires during construction using a model scale tunnelShow others and affiliations
2019 (English)In: Tunnelling and Underground Space Technology, ISSN 0886-7798, E-ISSN 1878-4364, Vol. 89, p. 50-67Article in journal (Refereed) Published
Abstract [en]
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, O 2 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 m 3 /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.
Place, publisher, year, edition, pages
Elsevier Ltd , 2019. Vol. 89, p. 50-67
Keywords [en]
Equivalence ratio, Self-extinguishment, Smoke spread, Tunnel during construction, Tunnel fire, Under-ventilated, Fires, Gas burners, Heptane, Open access, Propane, Smoke, Ventilation, Equivalence ratios, Smoke spreads, Tunnel fires, Tunnels
National Category
Natural Sciences
Identifiers
URN: urn:nbn:se:ri:diva-38351DOI: 10.1016/j.tust.2019.03.017Scopus ID: 2-s2.0-85063487886OAI: oai:DiVA.org:ri-38351DiVA, id: diva2:1314048
Note
Funding details: China Scholarship Council; Funding details: Myndigheten för Samhällsskydd och Beredskap; Funding details: RISE; Funding text 1: This work was financially supported by the Swedish Civil Contingencies Agency (MSB) and the Tunnel and Underground Safety Center (TUSC) which are gratefully acknowledged. Thanks to the advisory group consisting of numerous representatives from industry and authorities for valuable comments and support. Thanks also to Jonatan Gehandler for the support and our technicians for technical assistance in carrying out the tests. Besides, the authors would also like to acknowledge China Scholarship Council for providing Yongzheng Yao with the opportunity to study at Research Institutes of Sweden (RISE).
2019-05-072019-05-072023-06-08Bibliographically approved