| 摘要 |
PURPOSE:To restrain mechinery manufacturing cost, to restrain machinery weight and segment weight, to easily adapt to a construction environment in a big city such as acquisition of a site for vertical shafts, to minimize earth covering, to easily cope with setting of facilities such as expansion, contraction, branching and confluence of tunnel sections, and setting of an emergency parking belt, etc. with constant intervals and to carry out digging of a natural ground between tunnels without making a shielding machine excessively large even for middle-distance and short-distance tunnels of about hundreds meters and while performing an earth pressure countermeasure and a water stop countermeasure. CONSTITUTION:Tunnels 70 are connected to each other by digging and widening a natural ground 72 between the tunnels 70 dug adjacent to each other with a specified interval. In this case, water stopping and land slide protection are carried out by covering the natural ground 72 between the tunnels 70 by way of press fitting land slide protection plates 14 in the natural ground 72 between the tunnels 70 from a segment main body 12 constituting at least one of the tunnels 70. Thereafter, the tunnels 70 are widened and connected to each other by digging the natural ground 72 surrounded by the land slide protection plates 14. |
