Optimization and application of smooth blasting parameters based on radial uncoupling coefficient

For a rational selection of smooth blasting parameters, this study proposes a calculation method for the radial uncoupling coefficient ( K d ), based on the rock rupture mechanism under explosive load. The hole spacing ( h ) and the thickness of the smooth blasting layer ( w ) were also determined. A numerical analysis model was established to verify the accuracy of the calculated results, which were subsequently applied with success to the Tongchuan Tunnel project. The findings reveal that at the specific tunnel location of DK96+152, the optimal values for K d , h , and w were calculated to be 1.7, 0.5 m, and 0.6 m, respectively. The numerical simulation outcomes were found to align with the theoretical calculations. By applying the optimized smooth blasting parameters at the Tongchuan Tunnel construction site, the measured maximum overbreak distance was reduced by 0.27 m(64 %)compared to the pre-optimization period, and the overbreak area was decreased by 2.82 m 2 (57 %). This optimized approach resulted in the achievement of an ideal smooth blasting effect, demonstrating its potential to serve as a valuable reference for the rational selection of smooth blasting parameters in actual engineering projects.