Risk Assessment Of Underwater Tunnel Construction Progress Under Coupling Effect Of Various Influencing Factors

With the rapid development of urban construction and increasing traffic pressure,the available space of our city continue being squeezed.Simultaneously,construction scale of underwater tunnel project and investment quota is also constantly expanding.Compared with other ways of cross-river,underwater tunnel has the advantage of saving urban space,not being affected by climate,high reliability,not affecting navigation and other advantages,so its application is more and more widely.However,underwater tunnels are faced with complex construction environment under the construction,and they often are accompanied by difficult,complex technology,high water pressure,changing geology and other problems.These uncertainties will pose a risk to the construction of underwater tunnels,resulting in increased investment and waste of resources.Underwater tunnel construction progress risk research is still in the exploratory stage in the condition of coupling influence of various influencing factors,and the theoretical study of writing is relatively weak,even systematic guidance and practical guidance for the underwater tunnel construction schedule management are lack.This paper analyzes the risk factors in the construction of underwater tunnels and the coupling between the risk factors in detail,and the coupling relationship between risk factors is introduced into the risk assessment of underwater tunnel construction progress,thereby the evaluation of the construction progress of underwater tunnels can be further improve.First,based on the basic theory of risk formation and delivery,the study shows that the underwater tunnel is the process of forming the risk of construction and defines the way of risk in the form of mathematical quantification,to derive the formation mechanism of risk.At the same time,according to the general meaning of risk coupling,the coupling relationship between the risk factors of underwater tunnel construction is defined and the coupling mechanism and characteristics of underwater tunnel construction progress risk coupling are studied.Based on literature research,expert interview and WBS-RBS target decomposition method,this paper identifies the risk factors that affect the progress of underwater tunnel construction,constructs a coupling relationship network model for various kinds of risk factors,and expresses the relationship between the various types of risk factors clearly.Then,according to the construction schedule of underwater tunnel,this paper establishes the spatial hierarchical structure model of underwater tunnel construction progress evaluation under the risk coupling,including risk factor coupling analysis,risk coupling path sorting,and risk coupled chain metric analysis based on GERT network.And the risk coupling is introduced into the construction schedule evaluation system,combined with the construction progress network,the Monte Carlo simulation is used to simulate the risk distribution and the completion probability of the total progress,so as to provide more information for the decision makers.Finally,the method of this paper is used to analyze and validate the construction risk of the weft three-way crossing combined with the study of WeiSan Road in Nanjing across the Yangtze River channel.Through the establishment of the key risk chain,the key risk coupling path is determined,and finally the simulation is carried out to get the risk probability distribution and completion probability curve.And compared with the traditional engineering construction progress analysis,including the risk analysis scheme of the schedule plan,proves the superiority of the progress risk evaluation technology in this paper.This paper is based on the research of "Risk management and control technology of investment management of underwater tunnel project of WeiSan Road in Nanjing ".