A study of smooth wall blasting fracture mechanisms using the Timing Sequence Control Method

Our study also shows that, keeping the borehole spacing and borehole diameter as constant, a through crack can be formed between the adjacent boreholes when the delay time, spacing of PBH and TBH, and transverse wave velocity obey a certain relationship. Keeping the hole spacing between PBH and TBH, borehole diameter and the delay time for PBH and TBH as constant, borehole through cracks between the adjacent boreholes can be formed only when the spacing of TBH equal or below 25 times of borehole diameter.