Numerical simulation the effected of blasting vibration for different millisecond delay between the blast-hole

The vibration can be reduced by reasonable millisecond delay interval,and there have not accurate results of precision millisecond delay time for blasting. Based on seismic wave propagation of energy in the process of change and free surface,the millisecond delay time formula was given. Numerical simulation of different millisecond delay time for blast-hole. The results show that using the theory to calculated the millisecond delay interval,at the same time,the formation of free surface time must be considered to achieve the desired blasting effect. Blasting parameters of the case used in the simulation for the blasting vibration can be reduced when the delay time is 12 ms,at the same time satisfies the free surface formation time,favorable for rock fragmentation. The results also show that the calculation formula is feasibility.