Safety-Risk Transmission Assessment Based on a Factor–Event Network for Metro Construction Projects

Metro construction projects are accompanied by numerous unpredictable risk factors and risk events. Traditional safety risk analysis of metro construction projects focuses on risk factors of a particular risk event, such as collapse and falling. However, safety risk factors interact with each other and cause multiple risk events, forming a large transmission network. To reveal the influential relationship between risk factors and events in metro construction projects, the study proposes a safety risk transmission network model based on a factor–event network. First, safety risk factors and risk events were identified based on the reports of metro construction accidents in China. Then, a complex network containing 64 risk factors, 56 risk events nodes, and 533 interacted relationships was built. Finally, critical safety risk factors and risk events were obtained through quantitative assessment of the network topological feature quantity, and crucial transmission paths were identified. It was found that interactions between nodes were quite frequent risk factors of rainfall, geological voids, and illegal operations; and risk events of subsidence or cracks, earth and rock collapse, and death were crucial nodes in the network. These crucial nodes have a large influence on the network and play a pivotal role in risk transmission. Thus, project managers can develop a comprehensive long-term risk management plan based on critical factors and events and take measures to reduce losses by analyzing the risk transmission chains and taking measures to safeguard the neighboring nodes. It is of great significance for accident prevention, control, and improving safety risk management.