The Study Of Characteristics And Influence Factors Of Thermal Environment Of Long Highway Tunnel

With the rapid development of transportation industry in our country,and highway tunnel number increase sharply,motor vehicle will remove a large amount of waste heat in the tunnel and that cause the tunnel thermal environment is deteriorating.The high air temperature will affect seriously the normal operation of various kinds of equipment and motor vehicle,which threat people ′ s life and property safety.Therefore,it is great significance for operation safe of highway tunnel to study of thermal environment of long highway tunnel.This topic considering the thermal environment inside factors and outside factors,and be analyzed to formation mechanism of the thermal environment of long highway tunnel,set up the physical model of the air flow field of tunnel,the physical model of flow heat exchange of air and tunnel wall face,the physical model of heat transfer of tunnel surrounding rock and soil layer respectively.Based on the preprocessing software Gambit,the geometric model of long highway tunnel was established and grid mesh was generated,and the flow field and temperature field of the tunnel were simulated by the Fluent simulation software.The simulation to temperature field of rock and soil layer around the tunnel and air of one-way traffic long highway tunnel all year,the research finding that the air temperature grow up with the ventilation direction of tunnel,which is arrive peak and has a lag in the tunnel exit,the rock and soil layer around the tunnel can control air temperature effectively,because it absorb heat of tunnel in the initial operation,the tunnel surrounding rock and soil layer temperature response lag is bigger.Simulation research to thermal environment of tunnel for three influence factors of ventilation,soil and volume of traffic respectively,analyze the effect of different influence factors on the distribution and the change law of the temperature field air and layer of rock around the tunnel.Research shows that,compare with jet ventilation mode,the tunnel outlet temperature low range,lag small and the rock and soil layer around the tunnel small temperature rise of ventilation shaft line type and jet ventilation way of tunnel,which can be more effective and more lasting control of tunnel air temperature rise.In the simulation,it choose three types of soil as the tunnel surrounding rock and soil layer that is cohesive soil,gravel and grand,through the analysis and comparison,the granite can absorb or release heat of tunnel rapidly,at the beginning of the tunnel operation,which can restrain effectively the rise of air temperature in the tunnel,but a deep layer of rock will tend to be more saturated faster.With the increase of traffic volume,both temperature rise of air and rock layer have linear growth relation with volume of traffic,if increase the ventilation quantity according to design requirements of ventilation at the same time,which is basically the same.The temperature rise of tunnel exit is relatively severe at the initial operation of tunnel,and the thermal storage capacity of rock and soil layer around the tunnel(granite)is close saturation about 20 years.The simulation of thermal environment of one-way traffic long highway tunnel by the Fluent software,which found the distribution and the change law of the temperature field of air and layer of rock around the tunnel,comparison and analysis the different influence factors effect on thermal environment of tunnel,and simulation of prospecting forecasting of thermal environment of tunnel,which is made to provide reliable reference for the future to design of highway tunnel ventilation.