Correlations of Cerchar abrasivity index with geomechanical properties of intact rocks and its application to cutter life evaluation

Rock abrasivity is a critical factor to consider when assessing cutter wear and its service life during rock excavation. To determine rock abrasivity, the Cerchar Abrasivity Test is commonly used to derive the Cerchar Abrasivity Index (CAI) due to its effectiveness and convenience. In this study, 18 different types of intact rocks were selected for testing their geomechanical properties, including density, P-wave velocity (UPV), hardness (H), uniaxial compression strength (UCS), Brazilian tensile strength (BTS), elastic modulus (E), brittleness index (B) and equivalent quartz content (EQC). Subsequently, the correlations between CAI and these geomechanical parameters were analyzed. Simple and multiple regression analysis were conducted to obtain estimation models for calculating the basic mechanical parameters of rocks. The results of the simple regression show a strong positive correlation between CAI and UCS, BTS, E, H, B, and EQC. The correlation coefficients of CAI with each parameter are all higher than 0.8. By contrast, the multiple regression equations with higher coefficients of determination are more precise and reliable than simple regression equations. Finally, it was concluded that the Cerchar Abrasivity Index can effectively estimate cutter life and provide guidance for projects.