In the design and construction of reuse projects for closed mines, classifying the surrounding rock is crucial to ensure the integrity of the construction quality and minimize project expenditures. This study tackles this challenge by leveraging the plastic zone theory to select five critical parameters: initial rock mass quality classification, inherent rock stress, tunnel radius, lateral pressure coefficient, and support force. These parameters serve as revised benchmarks for classifying tunnel surrounding rock. Using FLAC 3D finite element software, the research conducts numerical simulations on a set of 25 cases, meticulously designed through a mixed orthogonal experimental methodology. The outcomes are analyzed using range analysis to establish a comprehensive understanding. This work goes beyond traditional frameworks, proposing an innovative grading methodology for surrounding rock that integrates the plastic zone proportion coefficient with relative deformation indices. This methodology aims to strike a balance between safety and economic viability, offering a holistic approach to tunnel stability. The proposed grading system is rigorously validated using fuzzy matter-element theory, confirming its theoretical soundness and practical feasibility. This study offers a robust and applicable grading framework by addressing the existing gap in methodologies for classifying surrounding rock in tunnel reuse projects in closed mines. This framework is set to improve engineering practices related to mine tunnels' rehabilitation and adaptive reuse, serving as a foundational pillar for future research and application in this field.

Plastic Zone Theory; Closed Mines; Tunnel Surrounding Rock Classification; Range Analysis; Fuzzy Matter-Element