Controlled blasting construction method null of base rock

摘要

PURPOSE:To carry out a controlled blasting efficiently without reducing the excavation speed by crushing and drilling the center of the facing of a tunnel by a static crushing means, and after that, crushing around the above crushed and drilled part by a normal blasting method. CONSTITUTION:At the center of the facing 1 of a tunnel, a crushed and drilled part 5 is formed by a static crushing means using no blasting, by using a rubber tube type rock crusher using a pressure liquid, for example. Then, bore holes 6 are engraved around the crushed and drilled part 5, an explosive is loaded, and the tunnel facing 1 is crushed in a normal blasting method. And the whole surface of the facing is not crushed and drilled, but only the center of the facing is crushed and drilled by a static crushing means, so as to reduce the rigidity around the facing, and the area around the facing can be crushed easily. Consequently, a noise and a vibration can be reduced, and the reduction of excavation speed can be prevented.