Study On Safe Evacuation Design Of Ultradeep Underground Public Space

With the intensification of the conflicts between man and land in cities,the shortage of urban land resources is becoming increasingly prominent,and the density of urban overground buildings is becoming increasingly saturated.The urgent situation of land resources has accelerated the development of underground space.The development of urban space has shifted from above to below.The development and utilization of underground space has become an inevitable trend for the sustainable development of cities.In recent years,the country has also issued a series of policy documents to promote the development of underground space.With the development of underground space,the deep expansion of underground space has become a trend.However,the development and utilization of ultra-deep underground space has the characteristics of large excavation depth,complex plane structure,multiple functions and uses,concealment and closeness of underground space,etc.Once disasters occur,serious casualty accidents will be caused.Therefore,the development and utilization of underground space,while bringing benefits to people,also brings increasingly prominent safety problems.How to evacuate a large number of people in underground space to the ground safely and quickly when a fire occurs is a technical problem that needs to be solved urgently.At present,the relevant codes in our country are mostly aimed at underground works such as shallow excavation,while there is no corresponding fire prevention regulations for safe evacuation of ultra-deep underground public spaces with a depth greater than 50 meters.In addition,the evacuation direction of personnel in underground space is consistent with the direction of smoke diffusion,which is from bottom to top.Therefore,the safe evacuation problem has become an important and difficult problem to solve.Starting from the architectural design level and combining with the requirements of relevant codes,this paper studies the evacuation of ultra-deep underground public space,focusing on solving the safety evacuation problems faced by ultra-deep underground public space in emergency situations.Firstly,the article explores the causes and characteristics of fires in ultra-deep underground public spaces,summarizes the hazards of fires in ultra-deep underground public spaces,and finds out the evacuation rules,thus establishing safe evacuation conditions.Then,based on the evacuation objectives,the paper summarizes the optimization design points of emergency evacuation facilities,horizontal evacuation and vertical evacuation in underground public space.Then,by analogy analysis,experimental testing,comprehensive application methods,BIM(Building Information Modeling)technology and pathfinder fire evacuation software,the existing safe evacuation mode and innovative evacuation mode are simulated and analyzed,and a variety of basically feasible combination schemes of horizontal evacuation and vertical evacuation are formulated,and the simulated evacuation results are summarized.Under the condition of meeting the safe evacuation time of personnel in ultra-deep underground public space,a reasonable safe evacuation mode for ultra-deep underground public space is obtained.Taking Hongtu Station of Chongqing Rail Line 10 as an example,BIM technology and pathfinder software are used to simulate the evacuation effect of the safe evacuation mode.Theoretical evacuation time and simulated evacuation time are compared to verify the effective feasibility of the safe evacuation mode in actual projects.Finally,the database of ultra-deep underground public space is established by BIM technology,and VR(Virtual Reality)technology is combined to assist in simulating underground space,so that personnel can be familiar with the space from a macro level,thus achieving the purpose of prevention and education.