Abstract: The Rock Block Index(RBI) is a crucial metric for assessing the integrity and structural characteristics of
rock masses. However,the traditional calculation method of RBI often leads to low correlation with the Rock Mass Integrity Index(
Kv) and significant deviations in integrity evaluation,as it overlooks the influences of varying regional lithology,structural
features,and in-situ stress conditions. To address this issue,this study takes a large-scale mine slope in western Sichuan as the
research object. Based on data from 28 exploration boreholes and 10 wave velocity test holes,the eigenvalue analysis method is
employed to replace the fixed weights in the traditional RBI formula with characteristic lengths corresponding to rock masses of
different integrity levels,and the classification boundaries are redefined,thereby obtaining a revised RBI. The research demonstrates
that the correlation coefficient between the revised RBI and Kv has significantly improved,along with a substantial increase
in the consistency ratio of rock mass integrity evaluation results and a notable reduction in cross-grade deviations. These
findings are further confirmed by validation group data. By introducing dynamic weights and characteristic lengths,this method
effectively overcomes the limitations of traditional RBI. It offers an economical and reliable alternative for rock mass integrity evaluation
in projects lacking wave velocity testing conditions,further enriches the connotation and application scenarios of RBI,
and provides a new approach for quantitative evaluation of rock mass integrity.

Key words: rock block index,rock mass integrity,characteristic length,rock mass quality