ROCK BENCH EXCAVATION METHOD BY BLASTING, GROUND EXCAVATION METHOD BY BLASTING AND EXCAVATION METHOD BY BLASTING FOR FORMING INCLINED SURFACE ON ROCK

摘要

PROBLEM TO BE SOLVED: To provide a rock excavation method by blasting capable of raising blasting efficiency by suppressing pollution caused by blasting.;SOLUTION: The rock excavation method uses a blasting mechanism comprising the steps of sequentially drilling holes consisting of a first row of primary blasting holes and a second row of secondary blasting holes respectively arranged on straight lines in an upper free surface of a rock bench having two free faces of the upper free face and the inclined free face or in a free face of a rock having one free face, filling the holes with charges, detonating the charges in the primary charge holes to form four free faces around the secondary blasting holes, and detonating the charges in the secondary charge holes in conditions that the four free faces are secured. This mechanism can regulate sizes of crushed rock, uniform the bottom face of the crushed rock and can execute excavation by blasting fitted to the conditions of the site. The mechanism can be applied to ground excavation by blasting for early blasting with one free face and pre-crack excavation by blasting for forming an inclined face.;COPYRIGHT: (C)2002,JPO