| More and more new subway stations today are restricted by many factors such as heritage protection,building restrictions,traffic security and existing route interchange relationships,etc.,and need to meet the structural and functional requirements with special station forms,which makes the safe evacuation of people more complicated,so it is very important to study the fire smoke movement.Therefore,it is very important to study the fire smoke movement and the shortest evacuation path.In view of this paper adopts a combination of numerical simulation and ant colony algorithm to study the fire smoke motion law and the shortest evacuation path of personnel in the overlapping stations,and provides theoretical support for fire rescue in similar stations.The main work and research findings are as following.(1)by combining with BIM technology,we overcome the problems of cumbersome modeling process and poor model accuracy of fire simulation software,and realize the linkage between the 3D building model and fire simulation model.The Deviation of simulation results caused by inaccurate models is effectively avoided.(2)Use Pyrosim software to set a fire source with a power of 3.0MW on the platform layer,and analyze three common fire scenarios(on both sides of the platform and in the center).Through the analysis of the fire products in the station under the three scenarios,it is concluded that compared with the fire in the westernmost and central part of the platform,when the fire source is located in the easternmost part of the platform,the fire products have the most serious impact on the evacuation of the people in the station,and are not conducive to the evacuation of the people in the station.When a fire breaks out on the westernmost side of the platform,fire products are most effectively contained after the fire.(3)Focusing on the study of the emergency evacuation path of trapped people and the application of intelligent algorithm in the evacuation model,Matlab is used to establish a grid map composed of obstacle vertices,define the static and dynamic attributes of nodes and evacuation channels in the evacuation space,and adjust the pheromone distribution.The heuristic function of the algorithm is enhanced by introducing personnel activity index,path difficulty coefficient and calculating equivalent length of evacuation path.The improved algorithm can effectively solve the problems of prematurity and slow convergence.(4)Determine the influencing factors of fire environment on personnel,quantify the influence of different road conditions,fire temperature,CO gas concentration and visibility on personnel evacuation speed,and configure the optimal combination of parameters by combining multiple simulation experiments:α is 1;β is 5;ρ is 0.6;Q is 10;m is 1.2.(5)Simulation of evacuation routes for the above three scenarios,the results show that the shortest evacuation path produces dynamic changes with the development of the fire,where the reason is that the fire develops over time,the power of the fire source gradually increases,and its combustion products have an increasing impact on the evacuation speed of the personnel,thus requiring constant dynamic adjustment of the evacuation path according to the law of smoke flow,and finally outputting the shortest evacuation path.This paper improves the ant colony algorithm by introducing dynamic parameters of fire,which can adjust the evacuation route in time according to the environmental conditions in the fire,reduce the time employed to escape,and improve the efficiency of personnel evacuation. |
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