Safety Risk Analysis And Control Of Subway Station By Cover-Excavation Reverse Construction Method

With the advancement of urbanization, the traffic pressure that confronting us is deteriorating. Because of the incomparable advantage, subway keeps rapid development and urban transportation system opens a subway era. The hub of subway is station, whose location is often selected in the downtown area of the city, which causes serious contradiction between the station construction and the normal operation of the city. Under the circumstances, cover-excavation reverse construction method is regarded as an appropriate solution for subway station construction. The cover-excavation reverse construction method has great safety hidden danger due to its complexity, which brings huge risk loss. So it is urgent to analyze and control the safety risk of cover-excavation reverse construction method for subway.Based on analyzing on the characteristics of cover-excavation reverse construction for subway station, the occurrence and control mechanism model about safety risk of cover-excavation reverse construction method for subway station is built from the disturbance-energy point refereed to the existing theory model. Compared with traditional model,this model adds a control mechanism in the system. This formation of risk is divided into four stages: latent period, gestation period, action period and closing period, including several major modules, such as the formation and control of risk factors, the running and control of risk factors, the action and control of risk factors.Using text mining tools, the text files of 67 subway station construction safety accidents from 2001 to 2015 were analyzed. Combined with the features of cover excavation reverse construction method, 20 safety risk factors were identified from four aspects, including "man- machine- environmental- management". And the safety risk list(including 118 risks) is identified based on WBS-RBS.In order to control safety risk events pointedly, a framework that used to analyze the association rules between a single safety risk factor(or multiple risk factors) and safety risk events is constructed based on Apriori algorithm. And it is verified in the basis of collapse risk events, studies show that geological environment, personnel quality, safety regulations, illegal operation and other individual risk factor have strong association with collapse events, 9 group safety risk combinations, such as "geological environment and safety regulations", "geological environment and illegal operation" also have strong association with collapse events.According to the occurrence and control mechanism model, the respective control strategy is proposed aiming at latent period, gestation period, action period and closing period, including the "prevent factors, control running, protect receptors, summarize and perfect". And the measures are proposed from organization, management, technology and other aspects to control safety risk of cover-excavation reverse construction method for subway station based on the results of risk identification and association analysis.