Comprehensive indicators optimization construction and lithology measurement while drilling based on drilling parameters

Lithology identification during drilling has become a crucial foundation for assessing instability risks of mine roadways and optimizing support design. This study aims to improve the accuracy of lithological identification by constructing more effective comprehensive indicators. To achieve this, the analytical relationship between drilling parameters and rock strength was established, and the method was proposed to construct comprehensive indicators including Modulation Specific Energy (SEM) and Rock Drillability Assessment (RDA) based on drilling parameters. The effectiveness, stability, and correlation of the comprehensive indicators in lithological identification applications were investigated. A decoupling model based on regression analysis of the rate of penetration ( v ) and SEM was proposed. Finally, the superiority of decoupled comprehensive indicators in lithological prediction was validated using Fitcsvm. The results demonstrate that the accuracy of lithological prediction using comprehensive indicators can be improved to 84% by eliminating the influence of v on SEM. This study contributes to the improved accuracy and wider application of lithological identification models during drilling under different experimental conditions.