###### Abstract  
Compared to the construction phase, the assessment of tunnel safety risks during the operational stage has not been thoroughly conducted, and the related research work is relatively lagging. To deepen the research and application of theoretical methods for assessing operational tunnel safety risks, and to improve the level of hazard investigation and prevention in long and large highway tunnels, this paper establishes a tunnel section assessment index system from four perspectives: tunnel condition, traffic characteristics, operational environment, and operational management. A combined qualitative and quantitative approach is employed, and a practical classification standard for the indicators is proposed. Based on the traditional Analytic Hierarchy Process (AHP) and fuzzy analysis theory, a new form of questionnaire survey, known as the expert system analysis method, is introduced to collect expert opinions. A novel approach for determining fuzzy numbers based on expert opinions is proposed. Consequently, a combined model for assessing operational tunnel safety risks in long and large highways is established by integrating the Fuzzy Analytic Hierarchy Process (FAHP) and the Set Pair Analysis (SPA). This model effectively combines subjective weighting with objective evaluation, thereby enhancing the accuracy of operational tunnel safety risk assessment for long and large highways. The safety risks of three long and large tunnels within the G1523 Yongguan Expressway were assessed using the evaluation method proposed in this paper. A comparative analysis was conducted between the results obtained using the proposed Fuzzy Analytic Hierarchy Process (FAHP) and Set Pair Analysis (SPA) method and the traditional Analytic Hierarchy Process (AHP) evaluation. The results indicate that the operational tunnel safety risk assessment method based on FAHP and SPA exhibits greater rationality and accuracy compared to the traditional AHP approach. highway; long tunnel; risk assessment; triangular fuzzy analytic hierarchy process; pairwise comparison analysis Article Research on Operational Safety Risk Assessment Method for Long and Large Highway Tunnels Based on FAHP and SPA  
[PERSON], R.  
1. Many operational highway tunnels still exhibit historical deficiencies inherited from their design and construction phases. During the operation process, the increasing vulnerability of these tunnels at specific locations highlights the emergence of safety risks for their subsequent management. 2. The current state of highway tunnel operation and management in China is characterized by weak operational management, lack of management information, inadequate safety facility provisions, inadequate maintenance, blind spots in monitoring and sensing facilities, incomplete disaster response plans, and challenges in addressing overloading and over-limiting issues. These factors contribute to an unsatisfactory tunnel operational safety situation. 3. The enclosed and narrow space within tunnels restricts the evacuation of trapped individuals and imposes greater limitations on emergency rescue operations. Traffic accidents resulting in multiple casualties and injuries, such as chain-reaction collisions, fires induced by primary accidents, and leaks of hazardous materials, still occur in long and large tunnels during their operational phase. Risk management refers to the management process of minimizing potential losses and negative impacts caused by risks in an inherently risky environment. In the 1970s, the United States took the lead in introducing risk theory in the field of tunnel and underground engineering and proposed characteristics and methods of risk analysis for underground engineering. Subsequently, scholars from various countries gradually integrated the theory of risk with railway and highway tunnels as well as metro construction projects, applying it to the planning, design, construction, and operation of engineering projects.