| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for constructing a flat tunnel, capable of allowing a flat tunnel of a low oblateness to be constructed, reducing the excavation quantity of spaces other than required spaces, and reducing construction costs.SOLUTION: A method for constructing a flat tunnel includes: a horizontal reaction securing step of connecting a start pilot tunnel 2 and an arrival pilot tunnel 3 to each other by a tie rod 4 (girth) to secure a horizontal reaction; an outer shell construction step of providing a plurality of pipe rows 10A jacked forward from the start pilot tunnel 2 to a natural ground and reaching the arrival pilot tunnel 3 so as to be arranged along the extension direction of a tunnel, and constructing an outer shell 11 of the tunnel by the plurality of pipe rows 10A, 10A ..., the start pilot tunnel 2, and the arrival pilot tunnel 3; and a tunnel cavity part forming step of excavating a natural ground 18 surrounded by the outer shell 11 to form a tunnel cavity part. |
