Full life cycle risk evaluation of the Weiyan high-speed railway based on the DEMATEL-FT-BN method

To address the critical research gaps in current high-speed railway risk assessment, investigate the safety status throughout the life cycle of the Weiyan high-speed railway and ensure construction, operational, and maintenance security, a three-phase analytical framework is developed. Firstly, the Decision-Making Trial and Evaluation Laboratory (DEMATEL) and Interpretative Structural Modeling (ISM) are combined to sort risk factors into clear hierarchical relationships, identifying key causal factors and their influence paths. Secondly, Fuzzy Set Theory (FT) is used to quantify uncertain expert judgments into reliable prior and conditional risk probabilities, solving the problem of ambiguous risk likelihood descriptions. Finally, Bayesian Network (BN) analysis is applied to model dynamic risk spread, enabling pre-accident risk prediction, in-process critical factor identification, and post-accident cause diagnosis. The main conclusions are as follows: (1) The full-life cycle risk of the Weiyan project is moderate, with a 59.7% probability during construction and 65.2% during operation-maintenance. (2) Sensitivity analysis identifies two top-priority risks: ineffective leakage of goaf grouting and high-speed railway equipment signal failure. (3) Post-accident diagnostic analysis shows that the main causal factors include insufficient goaf grouting depth, grouting leakage, ground subsidence anomalies, equipment signal failure, and improper railway line operation. Additionally, this framework helps practitioners prioritize controls and policymakers formulate full-life cycle safety standards, filling cross-phase risk linkage gaps in existing models.