关键词: 石墨矿, 爆破, 破坏模式, 能耗特性, SHPB, 高速摄影

Abstract: Under the blasting action,the problems of large fragmentation dispersion and low energy utilization exist in graphite ores of different grades. Dynamic compression tests of five grades of graphite rock samples with different strain rates were carried out with a ϕ50 mm SHPB apparatus. The impact failure modes and energy dissipation characteristics of graphite rock samples with different grades were studied by combining high-speed photography and microstructure. The study results show that as the grade increases,the failure mode of the graphite ore rock sample changes from tensile failure to tensile-shear failure. The energy consumption characteristics of graphite ore rock have an obvious strain rate effect. The incident energy increases exponentially with the increase of the strain rate,and the absorbed energy shows a linear growth trend;The grade also has a great influence on the energy absorption rate. The change characteristics of energy absorption rate with strain rate have obvious differences in graphite ore rock with different grade. There is a good correspondence between the average broken size of the graphite ore rock sample and the absorption energy. When the graphite ore rock grade is 18. 97%,the average broken size is the smallest. The microstructure of the crushed rock sample was observed through microscope. It was found that the graphite flake structure will produce structural interface in the ore rock and the strength of the ore rock was reduced accordingly.