This study presents a comprehensive approach to solve the problem of low ore recovery caused by the difficulty in separating small-particle size ore from soil after blasting in a limestone building stone mine.Firstly,a correlation model between blasting fragmentation and dynamic damage of rock mass was established based on field measurement data and numerical simulation results,which can determine dynamic damage thresholds corresponding to various rock particle sizes.Secondly,the numerical simulation test of bench blasting in a three-dimensional frac-tured rock mass was carried out by using different air-decked charging stages and borehole distribution parameters,which can improve the particle size yield of 0.3～0.9 m and control the bulk ratio to obtain the best blasting param-eters.Finally,the field blasting tests were conducted to optimize the charge structure and borehole distribution param-eters based on numerical simulation results.The results show a negative exponential function relationship between the blasting block size and the dynamic damage value of the limestone.Specifically,the dynamic damage thresholds cor-responding to the blasting size of 0.3 m and 0.9 m are 0.793 and 0.286,respectively.Using only an air-decked charging structure alone can increase the particle size ratio of 0.3～0.9 m and significantly raise the bulk rate.Con-versely,combining an air-decked charging structure with a reduced hole spacing markedly enhances the particle size ratio of 0.3～0.9 m while maintaining a stable bulk rate.Optimal blasting results are achieved using a two-stage air interval charging structure and a strategic reduction in hole distribution parameters.The field application results show a 20.09 percentage point increase in the 0.3～0.9 m particle size ratio,with the bulk rate remaining virtually un-changed.Additionally,the unit consumption of explosives decreased by 10.29％.
关键词
爆破块度/岩体损伤/空气间隔装药/裂隙岩体/数值模拟
Key words
blasting fragments/rock damage/air-decked charge/fractured rock mass/numerical simulation
维普
万方数据