Research on testing and controlling techniques of millisecond delay blasting vibration in coal mine rock roadway

In order to improve the blasting effect and reduce the blasting vibration in hard rock roadway,the millisecond delay blasting parameters were optimized and implemented,and the velocity of blasting vibration was measured.The correlation between blasting parameters and characteristics of blasting vibration signal was analyzed.For delay errors of electric detonators,the method of time-energy density analysis based on wavelet transform was adopted to identify the real delay time in millisecond blasting,and technical measures for reducing the blasting effect were put forward.The results show that a good blasting effect could be obtained by using reasonable millisecond delay blasting parameters,and the vertical peak particle velocity of blasting vibration can be taken as safety criterion for rock roadway.The method of time-energy density analysis can identify the blasting moment of detonators and ascertain the real delay time effectively.