WIDENING METHOD OF EXISTING TUNNEL AND DEMOLITION METHOD OF THE EXISTING TUNNEL

摘要

PROBLEM TO BE SOLVED: To efficiently carry out widening work of a tunnel while using the existing tunnel just as it is.;SOLUTION: In a method for constructing a new tunnel 2 by mounting a protector 15 on the inner circumferential surface of the existing tunnel to carry out the widening work in an approximately concentric circle on the outer circumference of the existing tunnel 1 while using the existing tunnel 1 just as it is, a bedrock 7 between a horizontal line X at right angles to the tunnel axial center 3 and the upper section 2a of the new tunnel 2 is excavated along the direction of the axis of the tunnel in the vicinity of the upper part of the upper end 6 of the existing tunnel 1, and after the excavated surface has been supported, bedrocks 8, 8, 9 and 9 between the sides 1b of the existing tunnel 1 and the sides 2b of the new tunnel 2 have been excavated in the direction of the lower part of the tunnel and in parallel to the direction of the axis of the tunnel, the excavated surface is supported to demolished the existing tunnel.;COPYRIGHT: (C)2004,JPO