Numerical Simulations Of Fire In Midi Tunnel And Research On Safe Emergency Evacuation

As one of the city's three-dimensional transportation methods,highway tunnels have played a significant role in alleviating traffic pressures and solving the difficulties of crossing major rivers and rivers.At present,the number of construction projects for mountain tunnels has grown rapidly in China.Due to topographic constraints,the construction of tunnel projects in mountainous areas can bring advantages to the surrounding environment and the production and living of residents along the route.The rapid development of highway tunnel construction has led to a rapid increase in traffic volume.Undoubtedly,the continuous emergence of a large number of long and large highway tunnels has made road tunnel disasters,especially road tunnel fires,a major hidden danger affecting the safe use of highway tunnels.This article relies on Midi abuilding curved highway tunnel project.Through theoretical analysis,numerical simulation and other methods,this paper systematically analyzes the temperature,smoke flow control,and personnel evacuation of Midi's curved tunnel under the scale of 20 MW fire,and applies the analysis results in the curve of the Midi's tunnel project.The main researches of this article are reflected in the following aspects:(1)Acquired statistics of major highway tunnel fire accidents and analyze the causes of tunnel fire accidents.(2)Based on the analysis of fire ventilation theory of highway tunnels and the ventilation methods commonly used in tunnel engineering,a three-dimensional numerical simulation model of a curved curve tunnel is established based on the specific engineering parameters of the curve tunnel of Midi,and the boundary conditions for numerical simulation are determined.Based on the analysis and statistics of domestic and foreign data of large-scale tunnel fires,the fire source setting method for the numerical simulation of the curve tunnel of Midi was determined,and the fire scale was selected.(3)The numerical simulations of the upstream and downstream tunnels of Midi are performed.In accordance with the design requirements for the critical wind speed of the tunnel in the tunnel engineering design specification,numerical simulations of the ascending and descending tunnels under the six operating conditions were conducted.By analyzing the conditions of smoke propagation in up and down tunnels under different operating conditions,the critical wind speeds of the upstream and downstream tunnels of Midi are determined respectively.(4)Under the condition of critical wind speed,the distribution of temperature and smoke concentration in the longitudinal direction of the tunnel when a fire occurs in the up tunnel and the down tunnel of Midi is studied respectively,and the maximum patience value of the human body with respect to the temperature and the concentration of the smoke gas is determined.The safety evacuation time ASET of the upstream and downstream tunnels in the event of a fire provides data support for subsequent personnel emergency evacuation studies.(5)On the scale of 20 MW fire,through the use of theoretical analysis methods,the necessary evacuation time RSET for personnel emergency evacuation after the fire in the curve tunnel of Midi was determined,combined with the available safety evacuation time ASET to discuss the design of the curve tunnel construction scheme for Midi whether the pedestrian or crosswalk design is reasonable.(6)Proposed the evacuation of people in the event of a normal fire situation and in the case of congestion,the evacuation of the tunnel in the case of a sudden fire in the Midi tunnel,and put forward suggestions for the implementation of the rescue in the case of a sudden tunnel fire in the Midi tunnel.