Estimation of Uniaxial Compressive Strength of Underwater Rock and Prediction of Powder Factor Using Blast Hole Drilling Parameters

To address the challenge of real-time adjustment for unit explosive consumption in underwater drilling and blasting operations, this study proposes a predictive approach for estimating the uniaxial compressive strength (UCS) of rock and determining the optimal explosive unit consumption based on borehole drilling parameters. Utilizing drilling pressure(F), rotational pressure(N), and drilling rate(V) as principal borehole drilling parameters, a linear regression analysis was performed to derive a predictive equation correlating these variables with the rock′s UCS. Based on the correspondence between explosive unit consumption and rock firmness coefficient, and incorporating depth correction factors, the analysis reveals consistent consumption patterns under identical water depth conditions. For sandstone and shale formations, explosive consumption remains consistent across different depths: 0.65~1.00 kg/m at 0 meters, 0.88~1.36 kg/m at 10 m, 0.93~1.43 kg/m at 20 m, and 0.94~1.45 kg/m at 50 m. Similarly, siltstone and mudstone exhibit identical consumption rates: 0.25~0.65 kg/m at 0 m, 0.34~0.88 kg/m at 10 m, 0.36~0.93 kg/m at 20 m, and 0.36~0.94 kg/m at 50 m. The proposed real-time adjustment method facilitates dynamic optimization of explosive specific charge, offering practical guidance for minimizing explosive consumption and enhancing blast efficiency in underwater drilling and blasting operations.