Dynamic rick management model for the construction of mountain tunnel

Besides the enhanced construction techniques,dynamic risk management is also critical to prevent unexpected accidents during the construction of mountain tunnel.The potential risk factors of mountain tunnel construction can be expressed with risk management method.The method is able to analyze and control the gusty risk during the construction.Based on fault tree analysis and expertise assessment, the potential risks in every phase of mountain tunnel construction were put forward;the causes and results of potential risks were analyzed.According to the dynamic management flow of mountain tunnel construction,a set of risk factors and risk assessments were obtained.The dynamic risk management model was constructed by introducing theory of membership matrix and entropy coefficient. The model adopted quantitative analysis as characteristics;it was able to execute computation of risk probability of the top events,dynamic risk analysis and operating mode control during the construction process. By referring the construction of Changchengling mountain tunnel for Baofu highway in Hebei province as case study,the proposed dynamic risk management model was applied to analyze the working procedures in the portal excavation stage.Based on the proposed fault tree of mountain tunnel portal excavation stage as well as the design data,field testing data and the expertise analysis result,the grades of risk probability and risk loss were obtained.The corresponding management and control measures for varied risks were brought forth by the risk grade.Due to promptly feedback and accurate reflection on dynamic change of risk,the probability for accident to happen was able to be forecasted and the safety of construction could be better guaranteed.