Safety Risk Management In Construction Stage Of Qingpingchuan Tunnel Project On Yulan Line

In recent years,China's transportation industry has developed rapidly,especially on highways.However,the traffic capacity is saturated in some areas,leadi.ng to Normalized traffic congestion.So it is imperative to improve service level,shorten the transportation distance,and realize the efficient transportation.But in high-level lines,the proportion of bridge and tunnel mileage in highway will be very large.Tunnel construction belongs to underground operation,with large investment,long construction period,great technical difficulty,bad working environment,complicated risk factors and frequent accidents.Therefore,the risk control of tunnel construction is the necessary means to control the investment and construction period.On the basis of the previous research,this paper takes Qingpingchuan tunnel of'Yulan line as the research object,carries on the r-isk identification alnd e-valuation to the whole tunnel construction stagesfinally puts forward the corresponding control strategy to the risk source of different levels.Qingpingchuan Tunnel,located in the north.ern Shaanxi Plateau,.is a collapsilble loess tunnel with many risk factors*First of all,the WBS-RBS method is used to identify the risk source.According to the construction process,the r~isk existing in each sub-project is analyzed one by one,and the coupling matrix is fornmed to identify the risk source in an all-round way.On the basis of this,two fault trees are established,in which the Portal Instability and Collapse of tunnel body are the top events.Secondly,,this paper adopts expert evaluation method,questionnaire survey method and statistical analysis method to obtain the occurrence probability of each risk sources.Meanwhile using fault tree model,this paper calculates the probability of each fault tree top event of Qingpingchuan tunnel construction project by programming,and the impact of each basic event on the top e'vent.And then this paper finds the most sensitive factors leading to the occurrence of the top event according to the size of the sensitivity order.Finally,according to the results of the analysis,the control measures are put forward to ensure the construction safety of Qingpingchuan tunnel.The main conclusions of this paper are as follows:1)the WBS-RBS coupling method is used to analyze the risk sources of Qingpingchuan tunnel construction stage,and on this basis,the fault trees are established.2)by using the fault tree model and algorithm,the probability of the base events and the sensitivity of the basic events to the top events in the construction stage of Qingpingchuan Tunnel are calculated by the program.3)according to the calculation results,the safety control measures of Qingpingchuan tunnel during construction stage are put forward.