Coupling analysis of multiple risk factors in deep foundation pit construction of metro station based on the N-K/SNA model

From a systematic perspective, the triggering mechanism of safety risks in deep foundation pit construction at metro stations results from the coupling among multiple risk factors. To scientifically explore the mechanisms of risk factors in deep foundation pit construction at metro stations and prevent safety accidents, the N-K model and SNA model are introduced to explore the interaction and coupling of safety risks. According to the collected data of 197 metro station foundation pit accidents over the past 30 years, a risk factor system comprising five primary risk factors and 36 secondary risk factors is established. Subsequently, based on the analysis of coupling mechanisms and risk network characteristics, key risk factors are determined by combining the coupling effect evaluation from the N-K model with the centrality and accessibility analyses from the SNA model. The results indicate that multi-risk coupling should be avoided during the construction stage of deep foundation pits at metro stations. Considering the coupling effect, the risk factors such as poor awareness of personnel security, insufficient professional skills, and insufficient safety investment are the key risk factors that require attention. These research results can serve as a theoretical reference for enhancing safety management and control for deep foundation pits at metro stations.