CONSTRUCTION METHOD OF THREE-ARCH EXCAVATION TUNNEL, FOR REDUCING TERM OF WORKS AND CONSTRUCTION EXPENSES BY EFFECTIVELY USING TUNNEL EQUIPMENT

摘要

PURPOSE: A construction method of a three-arch excavation tunnel is provided to shorten a term of tunnel excavation work by installing charge holes of a main tunnel through a combined process in constructing a pilot tunnel. CONSTITUTION: A construction method of a three-arch excavation tunnel comprises steps of blasting a pilot tunnel(10) for intermediate wall body construction; constructing shotcrete and a rock bolt to the pilot tunnel; radially boring charge holes(20a,30a) toward main tunnels(30,20) of the right and left sides of the pilot tunnel; constructing an intermediate wall body in the pilot tunnel; boring a charge hole in the tunnel end direction in the excavating boundary line of the right main tunnel and executing blasting excavation; and boring a charge hole in the tunnel end direction in the excavating boundary line of the left main tunnel and executing blasting excavation.