| 摘要 |
PROBLEM TO BE SOLVED: To provide a shield excavation method and a shield machine for improving the ground in a lower part of a segment while excavating by maintaining attitude of a main body part properly and facilitating and reducing ground improving work after forming an excavated pit. SOLUTION: A center runner 61 for pressing in ground improving agent is installed on a bottom face of the main body part 10 of the shield machine 1, and a lower step supporting arm 20a capable of tilting forward and freely in the vertical direction is provided. The lower step supporting arm 20a is provided with lower step center small drum cutters 32a, 33a at the center and lower step side large drum cutters 31a, 31a on both sides, and the latter have a drum close to the center, a drum close to a side, and a jack for extending and contracting for changing an interval in the direction of width between both of them. Consequently, if width of excavation of the lower step side large drum cutters 31a, 31a is reduced and the lower step supporting arm 20a is put down and is fallen down for excavation, an excavated part being a channel bar having smaller width than that of the main body part 10 is formed in a lower part of the main body part 10. COPYRIGHT: (C)2007,JPO&INPIT |
