| 摘要 |
PURPOSE:To speed up the widening work of a tunnel by disposing each fiber reinforcing bolt in the widened portion of an existing tunnel, and also enabling the tunnel together with its natural ground to be easily cut off. CONSTITUTION:Each natural ground improving material injection pipe 1 is made up of a hollow steel bar section 2 which is to be a positioned at a natural ground E2 on the outside of a face scheduled to be lining surface 30 for a main pit 12 after an advanced connecting gallery 11 has been excavated for widening, and of a hollow glass fiber bolt section 4 which is disposed in a natural ground E1 at the widened portion of a tunnel while being communicated with the steel bar section 2. After the natural ground improving material injection pipes 1 have been driven in the surrounding natural ground out of the advanced connecting gallery 11, the injection of natural ground improving material through each injection port 2a out of feed hoses 4a and 4b into the surrounding natural ground permits a natural ground improved body 31 comprising natural ground improving material mixed in the natural ground to be formed in the natural ground E2 around the main heading 12, and thereby permits the natural ground E2 to be stabilized. When widening works are carried out by excavating the natural ground around the advanced connecting gallery 11, each glass fiber bolt section 4 buried in the natural ground E1 in the widened portion can be easily cut off together with the surrounding natural ground, therefore, it will never be in trouble against widening works. |
