Simulation Study On Emergency Evacuation Of Pedestrian Passage Connecting Shopping Mall And Subway Station

Since entering the 21st century,with the continuous development of economy,China has shifted the focus of urban development from the ground to the underground.The construction of underground pedestrian passage connects the subway station with the comprehensive shopping mall,which not only creates convenience for people,but also promotes the prosperity and progress of urban economy.However,once an accident occurs,it will cause a large number of casualties.Therefore,improving the evacuation efficiency is the focus of future research.In order to alleviate the pressure of personnel evacuation caused by excessive pedestrian flow,this paper takes the pedestrian passage connecting a shopping mall and a subway station in Chongqing as the research object to study the personnel evacuation.Firstly,the relevant data were collected through on-site investigation to theoretically analyze the dangerous and harmful factors of human stampede and fire accidents;Then the Pyrosim software is used to simulate the fire smoke,mainly analyzing the spread of smoke and the changes of temperature,visibility and concentration on site;Then use Pathfinder software to simulate and analyze the impact of personnel differences on evacuation results,and combine the smoke simulation results with evacuation software to analyze the evacuation of personnel under different fire types and different location scenarios;Finally,it provides suggestions on evacuation routes and emergency measures for personnel in similar places to ensure the safety of life and property of personnel.This article reads as follows:（1）According to the on-site investigation,the data of the basic equipment and facilities,the flow of people and the distribution of people in the underground pedestrian passage were obtained,and it was found that the maximum time period of the evacuation pressure of the pedestrian passage was 8:00-10:00,18:00-20:00.Customers,the most important group in the evacuation,accounted for 83 percent of the total number of people in the passage.In addition,86 percent of the shops in the passage were food and beverage,clothing,and electronic products stores that were prone to fire,the fire-fighting facilities of these shops should be tested regularly to eliminate potential safety hazards and improve safety performance.（2）Pathfinder was used to analyze the performance of evacuation.It is found that the gender difference has little effect on the evacuation result,but the age and the shape of the personnel have more obvious influence on the evacuation result.In terms of body shape,the average shoulder width was 34.8 cm for men and 42.7 cm for women,and the average body thickness was 27.7 cm for men and 25.4 cm for women,the average height of 126.5 cm male children and 117.8 cm female children,under the same conditions,these groups of people evacuated the longest.（3）Different area per person has significant difference to the efficiency of evacuation.The pedestrian passage is often restricted by type C（the area per person is 0.3-0.78）²)during the peak period of pedestrian flow,and the restricted time is about 120s.Further simulations of stampedes at different locations showed that the area per person would be less than 0.38)²,at which point people would be unable to walk,and the evacuation time would be significantly longer,at least 176 seconds.In order to reduce the probability of trampling accident and the injury caused by trampling accident,an emergency evacuation plan is designed for the pedestrian passage.（4）Using Pyrosim software,three numerical models of fire scene were built,and 15detectors were set up to monitor the temperature,visibility and concentration of fire scene.According to the results of fire simulation,Pathfinder is used to simulate the evacuation of people in different locations,and the longest evacuation time is 308s.Then according to the safety evacuation time principle(T_RSET<T_ASET)and the safety performance analysis of the evacuation time,it is concluded that the evacuation pressure of the four exits in the middle of the passage is the biggest,147s after the fire,will gradually lose evacuation function and begin to pose a threat to personnel.In order to reduce the risk of fire and improve the efficiency of evacuation,emergency measures such as improving early warning system,adding spray system and adjusting the layout of shops were put forward.