Abstract: Classification of surrounding rock of moraine tunnels considering multiple factors is always complex and subjective. To address these problems, a set of multi-factor and two-level surrounding rock classification index system is proposed based on structural entropy weight method and credibility measure theory. The factors considered in the system include soil and water content, particle morphology, freezing-thawing effect, ground stress, and stone content. Additionally, the qualitative and quantitative description of each classification index is refined, and the recommended scoring interval and comment level of each index are provided. Subsequently, a surrounding rock classification model considering subjective and objective factors is constructed. The results show that the application case of a plateau railway tunnel in southwest China demonstrates high fit between the proposed method and other methods and strong inclusiveness and practical feasibility of the proposed method.

Key words: moraine tunnel, structural entropy weight method; credibility measurement theory, surrounding rock classification, freezing-thawing cycle, instance verification