Coupled Risk Analysis of Deep Foundation Pit Construction Risk in Civil Engineering Based on FTA and N-K Models

In order to analyze the coupling of the risk of deep foundation pit construction safety accidents, the risk coupling analysis of deep foundation pit construction accidents was carried out by combining the FTA model and the N-K model. By establishing the mapping relationship between the underlying events of the FTA model and the coupled risk factors of the N-K model, we calculate the single-factor, two-factor and multi-factor coupled risk probabilities and solve the risk coupling values by taking the three categories of human, environmental and management risk factors. The results show that: the risk probability of deep foundation pit construction accidents increases with the increase of risk coupling factors; when three-factor coupling, the coupling value is the largest; when two-factor coupling, the environment-management coupling value is the largest, with a value of 0.1820. The results of this study provide a reference for the risk management of construction safety accidents in deep foundation pits, which can help to reduce the occurrence of construction safety accidents in deep foundation pits.