Classification Method for Surrounding Rock of Highway Tunnel Based on Quantization of Tunnel Face Structure

By studying tunnel face images collected during a highway tunnel excavation, we establish the classification system of photolithography by MATLAB programming. According to the rock mass index (rock block size index or RBI) concept, 19 virtual lines are arranged in turn to the tunnel contour line, and the difference of the brazier rock mass structure is evaluated synthetically by 19 RBs of the radial direction of the face. Based on the structure, the distribution of comprehensive index of the rock mass structure (Z-RBI) is obtained through a comprehensive evaluation of the rock surface, and the corresponding relationship between the Z-RBI and rock structure type is determined. Considering the hardening degree of rock mass, the Z-RBI, groundwater condition, and initial geostress state, we propose the BP classification method for tunnel rocks, and we evaluated the BT method by using the analytic hierarchy process standard in an actual project. The comparison of the BT classification method and traditional BQ method reveals that the result of the former is more in accordance with the actual level of the excavated rock face than that of the latter method.