Real-time estimating method on rock strength via MWD of roofbolter and its application to in-situ grouting quality evaluation

Abstract Grouting reinforcement is an effective method for controlling fractured rock in the deeply buried roadways of coal mines. However, quantitatively evaluating strength grouted masses remains a challenge. The design grouting primarily based on empirical knowledge. Consequently, this study proposes real-time in-situ quality using measure while drilling (MWD) roofbolter. Initially, we validated through numerical discrete element method. Several 3D samples with varying crack densities were established and drilled numerically, demonstrating that can be better estimated drillability index rather than specific energy. Therefore, model, known as P d – R c was to estimate index. Subsequently, validation conducted self-developed MWD testing system assess masses. results show mass increases by 38%, 56.0%, 49.7%, respectively, after grouting, observed three boreholes. This allows quantitative estimation quality.