Research On Risk Management Of Deep Foundation Pit Construction Based On Fuzzy Sets And Improved Evidence Theory

With the rapid development of underground engineering,deep foundation pit engineering is widely used and its construction complexity and risk increase sharply.Deep foundation pit engineering has the characteristics of systematicness,regional difference,environmental sensitivity,dynamic and so on.As an important part of construction projects,its risk management has become an important part of project management.Due to the late start of the research in this field in China,there is no universal risk management theory for deep foundation pit construction.Starting from risk management,this paper focuses on risk assessment.In the process of risk assessment of deep foundation pit construction,the quantitative evaluation of influencing factors will be involved,and the quantitative index is mainly based on expert scoring.However,expert scoring is often directly related to the knowledge,experience and risk attitude of experts,showing obvious subjectivity and strong uncertainty.Evidence theory can better deal with uncertain information,improve the impact of human factors such as expert scoring and quantify the qualitative evaluation,making the evaluation results more reasonable.Firstly,on the basis of fully identifying the risk factors,the evaluation index system is established from the perspective of the main construction process.Then,a risk assessment model for deep foundation pit construction is constructed.The influence of extreme disadvantage value on weight is reduced by weighting each index with COWA operator,and the degree of each risk factor evaluation opinion belonging to different risk grade is determined by Gaussian membership function,which is regarded as mass function,and the evaluation opinions of multiple experts are synthesized by the fusion algorithm based on matrix analysis and weight distribution.And the linear weighting method is used to synthesize the mass function of each index,which can better deal with the problem of evidence synthesis under high conflict and reduce the time cost.Finally,combined with the 3A deep foundation pit project of Qingdao HJ project,the evaluation model is applied to the specific risk management of deep foundation pit construction for empirical study,and the main construction risks faced by the deep foundation pit project are evaluated.Accordingly,the corresponding control measures are formulated and the effectiveness of the model is analyzed.The validity of the model in the process of risk assessment is further verified,which can provide a useful reference for risk control in the follow-up construction process.