起爆位置对台阶爆破爆堆形态影响的离散元分析

爆堆形态是评估台阶爆破效果的重要指标,为研究起爆位置对台阶爆破爆堆形态影响,采用3DEC离散元软件,建立岩体强度参数服从Weibull分布的台阶爆破三维模型,通过考虑爆轰传播方向的荷载施加方法,模拟不同起爆位置下台阶爆破的动态破碎和抛掷过程。研究结果表明:在台阶爆破爆堆形态数值模拟中,不能简单地将爆炸荷载简化为瞬态爆轰,需要考虑爆轰波的传播方向。不同起爆位置下的爆堆形态存在显著差异,起爆点位置会影响鼓包运动最先发生的位置,从而影响岩块的抛掷方向和速度,影响爆堆的最终形态。孔底起爆时,爆破开挖方量最大,抛掷距离最远,堆积高度适中,松散系数最高,具有最好的铲挖效率。

Numerical Investigation of Initiation Points on Muckpile Profile in Bench Blasting

The muckpile profile is an important index to evaluate the effect of bench blasting.To investigate the effect of initiation points on muckpile profile,a bench blasting model considering the detonation direction,with its rock mass strength submitted to Weibull′s distribution,the 3DEC discrete element software was applied to simulate the bench blasting heave process.The results show that the blasting load cannot be simplified as instantaneous deto-nation,and the detonation propagation direction should be considered in numerical simulation.The detonation point location will affect the heave starting position of the movement,which has significant influence on the rock heave di-rections and velocities.Compared with top initiation and middle initiation,the bottom initiation method can achieve optimal muckpile profile with the largest excavation volume,biggest heave distance,highest loose coefficient and ap-propriate stack height.