Comprehensive risk assessment of urban underground space in China: an in-depth analysis of risk levels

Purpose As urbanization accelerates, the vital role of underground spaces in urban development has attracted increasing attention. At the same time, the associated hazards have become more pronounced, characterized by complex, interrelated, and mutually reinforcing risk factors. Therefore, assessing and analyzing the coupling mechanisms of these risks is essential for enhancing the safety and sustainability of urban underground environments. Design/methodology/approach This study initiates by delineating twelve risk factors, categorizing accidents recorded in China’s urban underground spaces between 2012 and 2022 into four domains: people, equipment, environment, and management. Through the application of Interpretive Structural Modeling (ISM), a hierarchical arrangement of these factors is qualitatively established, delving into the dynamics of their interconnectedness. Findings It is noteworthy that, in a specific case, the risk level of the empirical project was quantified through the cloud model based on Analytic Hierarchy Process (AHP) weighting and risk level assessment, and it was further obtained that the coupling degree between risk factors was above 0.9, indicating that the coupling level of risks was high. Originality/value The uniqueness of this paper lies in the introduction of a coupling perspective to consider the risk assessment problem within the scope of underground space. Through coupling analysis, the inherent mechanism of the transformation of single risk into compound risk is clarified, and the paradigm shift of risk management from fragmented response to systematic governance is promoted.