关键词: 自然崩落法　, 硬岩　, 爆破预处理　, 深孔爆破　, 参数优化　, 不耦合系数　, 数值模拟

Abstract: Proper cavability is a prerequisite for successful application of block caving in hard rock mines,but the high uniaxial compressive strength and the lack of developed joint cracks limit the initial and continuous caving of the rock mass.In order to explore the mechanism of the effect of blasting parameters on the pre-conditioning of hard rock by block caving,numer ical simulations were conducted based on Box-Behnken Design to investigate the effects of various factors such as borehole ap erture,uncoupling coefficient,and borehole spacing on indicators such as central crack length,crack rate,and crushing area ra dius.The expansion indicators of blasting cracks were optimized based on response surface methodology analysis and satisfac tion function optimization.The results show that the decouple coefficient is the main factor affecting the radius of the blasting fragmentation area.The decouple coefficient and the distance between blast holes have a more significant impact on the expan sion effect of blasting cracks,and are the main factors affecting the weakening area.The decouple coefficient is the main factor affecting the radius of the fragmentation area.When the borehole diameter and decouple coefficient are at a low coding level, the length of the central crack is larger.When the decouple coefficient and borehole aperture are both at a high coding level, the fracture rate generated after blasting is higher.However,when the borehole diameter is at a low coding level,the change in decouple coefficient has a more significant impact on the radius of the crushing area.The optimized blasting parameters using multi-objective optimization for hard rock are borehole diameter 165 mm,decouple coefficient 1.35,borehole spacing 10 m, with an overall optimal satisfaction function value of 0.904 6.The verification experiment shows that deep hole blasting can ef fectively improve the cavability and pre-conditioning effect of hard rock block caving.