Abstract:

The separated detonation of singlehole singlesection blasting should be carried out due to the limit of number of detonators. Hence, a new detonation circuit is proposed for the blasting excavation of tunnel laterally crossing dangerous building, i.e. using 20 sections of common detonator to carry out outerhole delay detonating between different detonation circuits and 3 sections of common detonators to carry out outerhole delay detonating in each detonation circuit. The field testing results show that by adopting the new detonation circuit: (1) the detonating time is reduced by 3 (from 5 to 2); (2) vibration peak of the new detonation circuit is almost as the same as that of original one; (3) the average vibration peak increases by 5%; and (4) no vibration superposition is identified.

Key words: tunnel laterally crossing dangerous building, outerhole delay detonating, vibration, detonating circuit