Research On The Model Of Pedestrian Evacuation In Bus Fire Accidents

Priority to the development of urban public traffic has already been the world’s common view in solving urban traffic problems, improving the urban air quality, and figuring out the city disease. While the bus is generally considered as a relatively safe means of transportation, but according to relevant data from China and abroad in recent years, the bus fire accidents occur frequently, and presenting the trend of increasing year by year. Relative to the other kinds of traffic accidents, the bus fire has higher possibility in causing a large number of casualties since its larger capacity and relatively smaller space. Experience shows that at the same time, when catching a fire the bus often burn out in a short time, resulting in a lot of economic losses. However, the research on bus fire accidents is insufficient, and most of them just focusing on the analysis of the factors of fires, there is a lack of in-depth study of mechanism of occupants movement in bus fires. For this sake, t his paper established and by then simulated an evacuation model considering the influences of fire and its product to simulate the occupants movement in bus fires.This paper resaerached the occupants behavior characteristics in bus fires. Through analyzing the evacuation video, we calculated evacuation total time and occupants’ average speeds in different scences from evacuation experimental results. According to the experimental data, we figured out both the occupants behavior characteristics and its influencing factors in bus fires. Besides, we emphatically studied the different characteristics between bus evacuation and building evacuation. Relying on the related information, we put forward evacuation personnel physical distribution model based on the characteristics of China citizens, and build out personnel individual reaction time probability distribution function based on the fire location and occupants’ own properties.This paper constructs the evacuation model based on fluid dynamics. Through the study of the stress analysis of evacuees, constructs the model of the fundamental forces.Abstract particle by personnel, the staff movement of fluid, the application description Navier-Stoke equations of fluid motion, converting the personnel movement to fluid dynamics problems, and the application of the Lagrange algorithm based on particle smoothed particle hydrodynamics(SPH) method for problem solving.Combined motion law and relevant laws of physics to modify the model, building meets the demands and the nature of the problem of smooth and kernel function, completed the basic evacuation model. Through the analysis of fire scenario and fire smoke, fire temperature influence on evacuation, random motion mechanism and personnel put forward the cumulative damage index, building fire scenario and its product influence module. More choice behavior exports, small group activities, driver behavior influence on evacuation, build based on the probability choice model, SPH method, following the evacuation of staff behavior characteristics affect module.Finally realize the bus fire evacuation model building.This paper implements the simulation of evacuation model to solve. By setting different position point of origin to determine different fire conditions, using the thermocouple temperature and flue gas heat equipment for fire scenario data, after the treatment as evacuation model based data. According to the evacuation of experiment personnel density, age, location, using the method of control variable of typical working conditions for simulation.Through the different situation, basic model and the effectiveness module can be determined. According to the results of simulation analysis verified the fire and its product and evacuees behavior affect the evacuation process. Compared with evacuation experiment results show that the established model can effectively simulate the actual personnel movement, has good application value.Compared with the previous evacuation model, this paper tentatively constructs bus evacuation model for the first time with the consideration of fire and personnel behavior factors. Then by using smoothed particle hydrodynamics(SPH), we solved the evacuation dynamics model, and based on this model we simulated different fire conditions. By comparing with the evacuation experiment results, the model was proved of its validity. The research results can be applied in the evacuation field, exploring personnel escape mechanism, and enacting correlative measures to reduce casualties.