Research On Basic Quality Index And Classification Numbers Of Engineering Rock Mass

Standard for engineering classification of rock masses is a multi-factor, multi-index, qualitative and quantitative rock mass classification method. As a unified standard of engineering classification of rock, it has been widely recognized since its enactment. Since the original test data is information collected from various departments in the extract, the database is improved and expanged with the extensive application of standards. The formula may need to make further adjustments with the improvement and expansion of the database. The argument of classification numbers is inadequate, it is needed to improve accuracy further for the best grade level. Therefore, this paper does a deep research on the basic rock mass quality index (BQ) and the classification numbers.Based on correlation analysis, partial correlation analysis, cluster analysis and reliability analysis, uniaxial compressive strength and integrity of the rock mass are selected as basic quality indicators from the nine classification factors. Classification is still divided into five gears. Inoder to increase the classification of poor rock mass, sub-classification is added on three and four degree. After adding the new data, based on regression analysis, new BQ is obtained, the new BQ formula limits and confidence intervals at both ends. Compared with the original BQ, the new increased the integrity of rock mass coefficient on the impact of engineering rock level.In the end, based on engineering examples, this paper compares BQ and other classification methods such as RMR and Q to identify their respective strengths and differences, to calculate the coincidence of different classification methods and derive the correlation between each type.