Abstract: Bench blasting is an important link in open pit mining. Its blasting effect directly affects the efficiency of subsequent shovel loading and transportation. Blasting design, rock properties, geological structure and other factors have a great impact on the blasting effect. In order to reduce the root and large blocks and improve the blasting effect, the optimization simulation study of blasting parameters is carried out based on the No. 9 pass lowering project in Zijingshan Gold and Copper Mine. The mechanical parameters of the rock were determined through experiments. Three groups of blasting models with different hole mesh parameters were established through LS-DYNA software. The stress nephogram of the initiation process was observed and the stress response of the blasted rock was analyzed. It was concluded that the peak tensile stress of the rock in the crack zone was the dominant role in its fragmentation. Then combined with the rock fragmentation theory, the peak tensile stress of the blasted rock under different hole network parameters is analyzed one by one, and compared with the dynamic tensile strength of the rock to judge its fragmentation effect, and the optimal hole network parameters are obtained. Through numerical simulation optimization and field test, the blasting effect has been significantly improved, and the efficiency of shovel loading and transportation has also been greatly improved. This model can provide a reference for the optimization of hole network parameters in similar blasting projects.

Key words: bench blasting, hole network parameters, numerical simulation, stress response, blasting effect