A new blasting approach of combined blastholes with different diameters is proposed to solve the problems of oversize boulders and rock toes in open-pit mine. A non-ideal detonation model and a statistical damage constitutive model are implemented in dynamic finite element analysis to investigate the formation mechanism of oversize boulders and toes. The damage distribution and evolution process of rock blasting fragmentation is simulated, and the scheme is further optimized. Numerical analysis results showed that pocket charges and satellite blastholes can only improve bench top fragmentation, but they cannot reduce the oversize in the middle and bottom of bench as well as the toe problem. The new blasting approach of combined blastholes with different diameters can effectively reduce the oversize boulders and toes as well as the production costs.

提出了一种新的不同直径组合爆破孔爆破方法，以解决露天矿巨石和岩趾的问题。在动态有限元分析中采用了非理想的爆轰模型和统计损伤本构模型，以研究特大巨石和脚趾的形成机理。模拟了爆破碎石的破坏分布和演化过程，并对方案进行了进一步优化。数值分析结果表明，袋装炸药和卫星爆破孔只能改善工作台顶部的碎片，但不能减少工作台中部和底部的超大尺寸以及脚趾问题。结合不同直径的爆破孔的新爆破方法可以有效地减少过大的巨石和脚趾，并降低生产成本。