METHOD OF DIAMETER-EXPANSION BLASTING CONSTRUCTION

摘要

PURPOSE: To improve the boring accuracy of an expanded hole and safety of the work by injecting a water jet or abrasive jet to form the expanded hole over a fixed range in a blasting hole and concentratedly charging and blasting explosives in the expanded hole. CONSTITUTION: After inserting a rotary rod 12 of a jet borer deep into a blasting hole 2, a water jet injection is started to destroy the wall of the hole 2 by a water jet injected from a jet nozzle 13 and gradually increase its diameter. When the total length of the expanded hole 3 reaches a length exceeding the total length of an explosive to be charged, the explosive is charged concentratedly in the expanded hole 3 and a filler is immediately tamped in the blasting hole 2 to blast the explosive.