Abstract:
In open-pit blasting, the minimum resistance line determines the dominant direction of blasting energy release and the maximum direction of rock velocity. This parameter is the core factor controlling the blasting action range, crushing effect and throwing path. Based on dem-pbm (discrete element method population balance model) coupling numerical simulation method of blasting crater, through the collaborative analysis of multi-scale modeling and test data, the field blasting crater test was carried out. The rock breaking law of blasting crater test under different minimum resistance lines is studied in order to optimize blasting parameters and improve blasting efficiency and safety. The results show that: the numerical simulation results based on dem-pbm show that the blasting expansion area increases by 70.33% year-on-year when w=1.05M, and 11.42% year-on-year when w=1.85M; Comparing the throwing effect of fragmentation under different minimum resistance lines, when w=1.05M, the throwing effect is the best; According to the field blasting crater test, when the length of the resistance line increases, the volume of the blasting crater becomes smaller, and when w=1.05M, the volume of the blasting crater is the largest, which is similar to the law of numerical simulation blasting cavity expansion; The fractal law of fragmentation size in field blasting is analyzed. When the resistance line is 1.05M and the depth of blast hole is 1.2m, more rock blocks are thrown, the fragmentation distribution is moderate, and the throwing effect of broken blocks is the best, which provides some reference for the optimization of field drilling and blasting parameters.
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