Risk assessment of metro construction based on dynamic Bayesian network

Recently, tunnel construction has developed rapidly in China. However, tunnel construction accidents occur frequently. In order to reveal the risk evolution process during the construction process over time, a dynamic tunnel construction risk assessment method is proposed based on the dynamic Bayesian network (DBN) and the fuzzy comprehensive evaluation method (FCEM). The settlement monitoring data induced by underpass tunnel excavation can be used to evaluate the real-time risk of above-ground structures by employing the proposed method. Twelve risk factors are classified into construction environment, construction technology, construction machinery and construction management. The causal relationship between twelve risk factors and tunnel construction risk is considered to build the DBN model, and the model is used to predict the evolution of risk during the construction process. The monitoring data of settlement and subsidence rate are used to update the assessment results of dynamic risk probability. The tunnel construction risk is evaluated by the fuzzy comprehensive evaluation method and the construction dynamic risk is calculated by the definition of risk. The reasonability of the proposed method is verified through the case of shield construction project of Beijing Metro Line 14. The results show that the proposed method can reflect the unexpected risk events in the actual construction process.