Research In Different Fire Scene For Highway Tunnel Composite Lining Structure Security

With plenty of highway tunnel in construction, various disaster, especially with frequent fire hazard, give people a significant impact of production and life. high temperature produced by tunnel fire will seriously affect the safety performance of the tunnel lining. Accordingly, evaluating the safety of lining and how to improve the fire performance has become an important problem.Refer to the fire case from all of the world, and through the results predecessors numerical simulation method, temperature distribution were studied in highway tunnel. This article analyzes the highway tunnel lining composite linings by strengthen the primary support and strength the second lining, and provide the reference for lining form prevention research.Through the highway tunnel fire case studies and the affecting factors of fire size, this paper summarizes the characteristics of fire hazard in tunnel and select the typical medium vehicle fire to analysis. Using CFD general software fluent and simplifying mathematical model to simulate the likely temperature distribution, established a tunnel vaults and arch waist place temperature-time curves. Using ANSYS software, Ground-structure was simulated in tunnel composite linings. the second lining structure in temperature field distribution and temperature stress size and distribution were given. Analyzed the change of temperature stress importance of early support and secondary lining of two kinds of circumstances. Research show that from fire prevention Angle, strengthen the temperature stress becomes the second lining, improves the safety of structure under fire. Refer to highway tunnel, and consider the design specifications of structure strength loss on safe, establishes the safety evaluation criteria.The main conclusion:1)when fire occurs, tunnel temperature field distribution is extremely complex and the combustibles heat release rate of fire and ventilation speed greatly influence temperature field distribution; Adopting HC heating curves 30MW fire for scale tends to fireproofing design safety.2)Internal tunnel lining temperature stress distribution is extremely uneven, maximum appeared in vaults pace,arch in neonatal and sidewall in minimum. 3)To strength the second lining cases, tunnel vaults place temperature stress reduce, in which the form of fire-protection design composition, this paper suggest to strengthen the second lining to improve tunnel fire performance.