Abstract:In order to solve the problem of inaccurate classification of surrounding rock of tunnel through rock pile, direct shear test of similar materials is used to analyze the direct shear characteristics of rock pile, and two factors of water content and soil content are used to the entropy weight extension matter element method, and the classification is studied in combination with geological indexes. The results show that with the increase of water content and soil content, the shear strength of rock pile first increases and then decreases, and finally becomes stable. Too high or too low water content and soil will "weaken" the shear strength of rock pile. According to the characteristics of rock pile, the rock uniaxial saturated compressive strength, joint crack density, rock integrity coefficient, water content and soil content were selected as classification indexes. Combined with the entropy weight extension matter element method, the selected indexes were combined with the entropy weight extension matter element method, and the classification results were verified in engineering examples. The accuracy of the classification results is better than that of the original method, which proves that the surrounding rock classification method proposed in this study is reasonable and feasible. The research results can provide guidance for the grading of rock pile tunnel, and provide basis for construction design and support method.