Optimization of reserved hollow hole full-section single blasting: Enhanced efficiency and safety via model-field integration

Combining model and field tests, this study proposes an optimized single blasting method with reserved hollow holes. Firstly, through model tests, key parameters such as blasthole spacing, charge quantity, and delay time (90 mm, 0.75 kg, 50 ms) were optimized, and the effects of different parameter combinations on fragmentation uniformity, PPV (mm/s), and energy utilization were evaluated. Secondly, field tests were conducted in a real mining tunnel with a semi-circular cross-section (5.2 m × 3.6 m) and Fair rock mass conditions, verifying the feasibility of the 90 mm spacing and other optimized parameters under actual geological and operational constraints. These tests demonstrated that the method is practical in engineering environments, achieving significant improvements in efficiency, vibration reduction, and fragmentation quality compared with traditional sequential blasting, the economic evaluation explicitly included drilling, tool wear, depreciation, labor time, and ventilation energy, in addition to explosives and cycle time. The test results show that single blasting reduces explosive consumption by 46.6 %, lowers unit resource consumption by 27.8 %, shortens operation time by 14.3 %, decreases PPV by 20 %, improves d50 (particle size) to 20 mm, reduces the impact on the high-risk zone by 33.3 %, and increases the support integrity rate to 90 %. These advantages remained after accounting for operational costs—drilling, equipment wear and depreciation, labor, and ventilation energy The above optimization provides scientific support for efficient and safe blasting operations and can be widely applied in engineering fields such as tunnel excavation and mining.