Risk Identification And Evaluation For Foundation Pit Construction Of Subway

With the development and utilization of urban underground space,the subway rail transit project,which as one of the important measures to improve the urban traffic condition and relieve the traffic pressure,has been paid more and more attention.However,because of the scale of construction of metro engineering and the complex and changeable of construction environment,the requirements of deformation of surface caused by excavation requirements is high.Therefore,strengthen the subway engineering construction safety risk control is an important link in the field of subway construction project.Due to the cross construction technology,the narrow construction site and a series of risk factors produced in the construction process,the probability and the loss of risk events is difficult to determine.Therefore,it is of great significance to establish a suitable risk assessment model for deep foundation pit construction to improve the risk management and ensure the safe construction of the foundation pit.(1)Based on the construction of deep foundation pit of a subway station in Xiamen and combined with the construction experience of similar projects at home and abroad,this paper establishes the construction risk list on the basis of fault tree analysis.(2)According to the construction condition of deep foundation pit,the main risk factors of the construction of deep foundation pit are analyzed and determined by WBS-RBS risk identification technology.(3)Through studying the coupling and correlation between risk factors,determine the weight of risk factors.Based on fuzzy theory and Bayesian network theory,the probability of occurrence of risk factors and fuzzy loss are estimated.(4)By establishing the trapezoidal membership function and evaluation model,the fuzzy comprehensive evaluation method is used to determine the construction risk grade of the foundation pit.(5)Finally,the validity and applicability of the model are verified by the example analysis,and the corresponding risk response and prevention measures are put forward.