Simulation Study On Urban Tunnel Personnel Evacuation Based On Different Fire Scenes

In recent years,the demand for urban cross-regional transportation has increased.In order to improve the urban traffic network and improve the quality of transportation facilities for urban commercial groups,urban road tunnels have been widely adopted in traffic construction.Urban tunnel traffic has the following traffic characteristics,namely: frequently,periodically traffic congestion/blocking,obvious day and night phenomenon,large traffic flow,large number of people,complicated traffic confluence and crossflowing intertwined sections,and the closedness of urban tunnel traffic environment Unlike ordinary roads,in the event of a fire,the consequences are extremely serious.The probability of fire scene occurrence,the scale of combustion,the law of fire development and the evacuation of personnel in urban road tunnels are quite different from those of non-urban tunnels.This paper uses literature research: theoretical calculation,formula derivation,traffic investigation,random sampling simulation,Numerical simulation and other methods,they are used to study the probability of urban tunnel combustion scale and the safety of urban tunnel fire evacuation.The research results can provide the basis for the actual engineering evacuation safety design parameters.The main work of the thesis is as follows:1 Through the investigation of the fire accident data of urban road tunnels,the statistical analysis shows that the cause of spontaneous combustion of vehicles accounts for 66.7%,and the cause of collision of vehicles is 25.5%.From the theoretical analysis of the mechanism of vehicle fire spread in urban traffic tunnels,the number of vehicles that can be ignited in different fire scenes in a two-lane one-way traffic tunnel is 0 or 1 or 2,and the three lanes are different when only one ignition situation is considered.The number of ignitable fires in a fire scene is 0 or 1 or 2 or 4 vehicles.2 The simulation code of the combustion scale occurrence probability of two-lane tunnel and three-lane tunnel based on Monte Carlo thought was written.The MATLAB platform was used to simulate the fire scene of millions of different working conditions,and the 25 MW combustion scale ignition of the two-lane tunnel was obtained.The occurrence probability of the scene is above 15%,and the probability of occurrence of the 25 MW combustion scale ignition scene in the three-lane tunnel is about 20%.Considering the probability of occurrence and the scale of combustion,the occurrence probability of 5MW,20 MW,25MW,30 MW,40MW and 60 MW is higher.3 Using 6 kinds of combustion scales as fire source boundary conditions,carry out the A-time numerical simulation of the evacuation safety of tunnel fires under the influence of multiple factors(ventilation factors,traffic factors,tunnel slope),and analyze the fire occurrence time in the tunnel Ventilation is the dominant factor affecting the time available for evacuation.Comparing the available time of different cross-section positions of tunnels,the safest value A available under different evacuation channel spacings of different fire scenes provides data support for the study of design parameters of evacuation channel spacing.4 Using the professional evacuation simulation software to analyze the time R required for the safety evacuation of people under different evacuation channel spacings,and use the evacuation safety index RA as the basis for judging the degree of evacuation safety of the personnel,and give the safety of urban highway tunnels under different fire scenarios.Estimated value of evacuation design parameters.Using the research results to evaluate the fire safety of the supporting project,it is safe to design the evacuation safety parameters in the supporting project.The conclusion of the paper can provide reference for the design of fire evacuation safety parameters for urban road tunnels of the same type.