Abstract: A bilinear symmetrical initiation technique is proposed to solve the problem of high bulk rate and bedrock when hard rock blasting.In this paper,the propagation characteristics of axial detonation wave of cylindrical charge under bilinear symmetric initiation are analyzed by combining numerical simulation with the standard test.The numerical simulation results show that the detonation wave produces positive reflection,oblique reflection,and Mach reflection in sequence when the bilinear symmetric initiation is adopted,which can effectively increase the detonation pressure inside the explosive.The detonation pressure can reach more than 1.75 times of the stable detonation pressure at the central point of initiation.Compared with the central point initiation,the detonation pressure value is more than 4.09 times of the stable detonation pressure on the crosssection edge perpendicular to the line between the center of the charge column and the initiation point.In the range of 32~80 mm charge diameter,the cumulative effect of detonation collision increases with the increase of the charge diameter.Compared with the lead block test results,the power capacity of the explosive can be increased by 14.5% (lead block test) and 17.1% (numerical simulation) when using the bilinear symmetric initiation method compared with the central point initiation method.The research results are of certain significance to study the mechanism of detonation collision energy accumulation,and provide a new method of reducing the blasting bedrock and improving the energy utilization rate of explosives.

Key words: cumulative detonation,linear charge explosion,detonation wave collision,initiation manner,numerical simulation