| 摘要 |
PROBLEM TO BE SOLVED: To prevent interference with an entrance of a projection by providing a fixing cutting blade frontward of the projection to the outside of a shield frame. SOLUTION: A fixing cutting blade 30 is provided frontward of a projection 16 such as a simultaneous back-fill agent injector in a shield frame 10. The entrance peripheral part of the shaft earth retaining wall of a starting shaft and a reach shaft is formed by using a new material concrete wall. The cutter 11 of the edge of the shield frame 10 of a shield excavator 3 directly excavates a new raw material concrete wall, so that in the case where an entrance is formed, a fixing cutting blade 30 attached to the shield frame simultaneously excavates at a position corresponding to the projection 16 such as a simultaneous back-fill agent injector of the new raw material concrete wall. Thereby when the shield cutter 3 is passed in the portal excavated by the cutter 11, the projection 16 interferes with the entrance to damage it, and reversely the projection 16 is prevented from being damaged. |
