| 摘要 |
PURPOSE:To construct large scale underground space such as a large-diameter tunnel in weak ground by using a comparatively small machine and by minimizing influence upon a ground structure and to excavate any cross sectional shape and any size. CONSTITUTION:Leading screw tunnels 2 for surrounding the excavated inner surface of a large-diameter tunnel 1 are provided on a plurality of places in the constructing large-diameter tunnel 1 in its shaft line direction. Then, small- diameter tunnels 4 for communicating the leading screw tunnels 2 with the large-diameter tunnel in its shaft line direction are adjoined to one another in the direction for surrounding the excavated inner surface of the large- diameter tunnel 1 for excavation. The small-diameter tunnels 4 and the leading screw tunnels 2 form the outer shell part of the large-diameter tunnel. Then, their insides are excavated. |
