Study On The Influence Of Tunnel Protection Structure Material On Tunnel Fire Characteristic

With the increasing demand of transportation, a large number of highway and railway tunnels have been built up, which has enriched the way of transportation. In the tunnel for the convenience of living, the fire hazards should not be ignored at the same time.Tunnel fire prevention is always an important topic in the foreign experts and scholars to study, so as to protect the tunnel structure is not damaged by high temperature, we not only need for the safety of person inside the tunnel, but also to the structure of tunnel, Tunnel fire commonly used maintenance structure for asbestos, perlite and all kinds of fire retardant coatings. And the study of the influence about different materials on the tunnel fire is relatively not to much at present. Based on the lessons of previous work experience, using the down size of tunnel fire experiment platform is designed and built, with gasoline pool fire as the research object, carried out a series of different boundary conditions and different size of pool maintenance and different longitudinal ventilation experiment, The research results are as follows:(1) For tunnel fire fire heat release rate, because of the closed space thermal feedback effect is enhanced, the pool fire’s burning time will is lower; Longitudinal ventilation on fire heat release rate has a role in enhancing, but when the wind speed is larger, the impact is not obvious. At the same time, the oil basin for the larger size, the smaller wind speed is also smaller influence on the fire heat release rate;(2) under different boundary conditions,The heat release rate is basically the same, when the pool size increases, because of the enhancement of thermal feedback effect, the heat release rate in asbestos plate boundary condition has improved; wind speed under the action of different boundary conditions and heat release rate is basically the same.(3) the boundary conditions change of fire is above the temperature field has a certain influence, in the smaller size of the sump, asbestos in the boundary conditions of fire in the vertical direction changes in temperature and glass boundary conditions of vertical temperature is basically the same, with increase of the sump size, with the same boundary conditions for source of vertical temperature effect is more obvious, both temperature compared up to 150℃. At the same time, with the increase of oil will make the heat release rate increases;(4)For Hu’s tunnel fire temperature along the attenuation equation, it ignores the wall for temperature decay of the impact of the situation. This paper through experimental think avoid attenuation of temperature has a great influence, so in the fire temperature along the attenuation formula should take into account the different boundary conditions, namely its thermal conductivity is brought about by the impact.