Simulation And Optimization Of Emergency Evacuation Routes For Indoor Fires In Large Public Buildings

The frequent occurrence of fire in large-scale public buildings is attracting great attention of the society.In order to solve the personnel evacuation problem and reduce the casualties and property losses as much as possible,this paper is based on the emerging BIM(Building Information Model)technology in the construction industry and take emergency rescue as the background,the simulation of the smoke spread and personnel rescue in case of fire has been carried out of optimize the building structure.Then,the personnel evacuation route is analyzed,and a multi-objective optimization model of route decision-making with shortest route and shortest time is constructed under the condition of considering evacuation scenarios and attributes of evacuees.Finally,the optimal evacuation route and shortest evacuation time are obtained by using ant colony algorithm and genetic algorithm.It provides a scientific basis for the study of safe evacuation strategy.Personnel evacuation situation in case of fire has been studied based on BIM technology,evacuation simulation technology in this paper.Then evacuation route and time are solved by intelligent optimization algorithm.The main research work is as follow:Firstly,the research status of BIM technology,emergency evacuation and intelligent optimization algorithm at home and abroad is summarized and analyzed based on the background of emergency rescue.On the basis of summary,a three-demensional model of evacuation scene is constructed.Taking a large university restaurant as an example,this paper consummates various parameters information,such as door,window,floor size information by means of the Revit software,and finally obtains a three-demensional model which is completely consistent with the actual structure information.The study has more practical significance.Secondly,fire smoke and personnel evacuation are simulated.Fire smoke is simulated by Pyrosim software,and smoke temperature,fire visibility and CO concentration are taken as calculation parameters to obtain the endurance limit time of indoor personnel under fire as the basis for safe evacuation.Personnel evacuation simulation is that BIM model is imported into Pathfinder software,and Steering mode or SFPE mode is selected to simulate the evacuation operation.The blocking position of evacuees is found to check the defects of the building structure through analyzing the pass rate of evacuees and the changing law of evacuees with time.It is beneficial to optimize the building structure.Finally,the optimization model of emergency evacuation route of indoor fire scenario is constructed,including geometric model and mathematical model.Thegeometric model simplifies the interior structure,such as simplifies the intersections,doors into nodes,connects the accessible nodes to form an evacuation route and draws a geometric network model of interior space based on graph theory.A multi-objective mathematical model of evacuation route decision-making is constructed by extracting the data from the geometric model.The model takes the shortest evacuation route and shortest evacuation time as the objective and takes the staff capacity at the nodes as the constraint.The basic ant colony algorithm,improved ant colony algorithm and genetic algorithm are used to solve the model.The superiority of the improved ant colony algorithm and the feasibility of the route optimization algorithm are verified through the comparison of the results.