Aiming at cemented tailings backfill (CTB) damage and collapse induced by secondary stope blasting in the sublevel open stoping with a subsequent filling method, a new CTB damage control technology termed “Synergistic Utilization of Cumulative Blasting Damage (SU-CBD)” is proposed. First, theoretical analysis is conducted to reveal the influence mechanism of rock mass damage accumulation on its blastability, verifying the feasibility of the SU-CBD technology. Subsequently, based on the LS-DYNA R11.1 software and RHT material model, a numerical model is established, and the small restart technique is adopted to realize the continuous simulation of multi-row blasting. By comparing the rock mass fragmentation ratio, energy distribution, and CTB damage degree among different charge structure schemes, the optimal charge structure combination is obtained. To address the issues of retained rock mass damage and overbreak caused by multiple blasting operations, a dynamic adjustment method for blasthole row spacing is proposed, with the optimal row spacing increment determined as 1.0 m. To verify the technical effectiveness, field industrial tests are carried out in Stope No. 5 of the 4500 m–4550 m mining level in the Bangzhong Zinc-Copper Mine. The results show that the optimized blasting scheme keeps the CTB intact without collapse and achieves uniform ore fragmentation, and the oversize ore ratio (particle size > 50 cm) is only 2.4%, with the numerical simulation results in good agreement with the field test results. The research indicates that the SU-CBD technology can effectively reduce the powder factor and CTB blasting damage while ensuring the blasting fragmentation effect, providing reliable blasting design support for the secondary stope.
Song et al. (Thu,) studied this question.