Identifying Core Safety Risks and Interrupting Critical Risk Chains in Urban Underground Space

To address the limitations of traditional single-perspective risk analysis in tackling the complex safety governance challenges of urban underground space, this study analyzes core safety risks based on 128 accident cases and constructs an integrated analytical framework incorporating static structural analysis, dynamic propagation analysis, and risk chains assessment. The research was conducted by applying association rule mining, complex network analysis, and temporal propagation models. Firstly, 36 standardized risks were extracted from four dimensions: human, machine, environment, and management. The effective strong association rules were mined using the Apriori algorithm, and the confidence values of the rules were used as the corresponding edge weights to construct a directed weighted risk network. Then, the network centrality metrics integrated through principal component analysis determined the static core risks. At the same time, based on the small-world network theory, a temporal propagation model was established to depict the dynamic propagation characteristics and extract the dynamic core risks. Through the comparative analysis from two perspectives, the core safety risks were finally determined. Then, the risk propagation paths were analyzed using depth-first search, the risk chains were evaluated through multi-index quantification, and the high-risk chains were identified. The results show that adverse geotechnical conditions, inaccurate geological surveys, safety leadership and duty deficiencies, insufficient or malfunctioning emergency equipment, internal water accumulation, and extreme rainfall and flooding are the key risks with high structural importance and propagation criticality. High-risk chains are primarily triggered by geological hazards, propagating through environmental and equipment nodes before converging on management defects; management risks act as critical convergent nodes in most risk chains. Based on these findings, this study proposes a targeted intervention strategy that integrates source control and chain interruption, providing methodological support and decision-making references for the safety governance of urban underground space.