In order to study the influences of interval charge length of the open deep-hole blasting on the rock crushing, propagation change rule of explosive stress in the rock under the condition of different interval length and resistance line is studied in this paper based on ANSYS/LS-DYNA finite element numerical simulation method. The simulation results show that the interval length is related to the resistance line. When the interval length is a fixed value, there would be a critical length of resistance line. The two linear charges act on the rock alone, boulder yield will be increased between interval medium and the free face, and the utilization rate of the blasting energy will significantly reduce, when the length is less than the critical value. Through the analysis of the stress change rule, the interval length is better to take less than a third of resistance line in the open deep-hole blasting and other blasting engineering.
In the open-pit metal mines, blasting effect not only has a significant effect on the mine production, but also has a direct impact on the blasting cost. The traditional continuous cylindrical charge structure leads to higher unit consumption, lower economic value, over crushing and bigger blasting vibration damage, etc. (Wu et al. 2010). In recent years, the study of interval charging is unceasing at home and abroad, and this technology is applying to the production practice. In Russia, the unit consumption of explosives was reduced by 10%-30% and the crushing effect has improved significantly with using the technology. Australian researchers used interval charging technology to reduce the production cost and controlled the blasting vibration damage at the same time (Wang & Yu 1995). Numerical simulation study on the stress wave transmission of interval charge in the rock is made by Li shunbo and transmission characteristics of the stress wave in different medium and distribution of the blasting energy had been got in this study (Li et al. 2012). In this paper, the numerical simulation method is used to research the relationship between the resistance line and interval length according to the characteristics of stress wave (Zheng 2009).
