| 摘要 |
PROBLEM TO BE SOLVED: To prevent breaking of a cutter, particularly during excavation of a hard wall, by cutting a wall in front of a back-filling injection pipe projected form the outer surface of a shield main body. SOLUTION: A storage recess 11 is formed in an opening 9 formed in a shield main body 2 located in front of a back-filling material injection pipe, and a rotary cutter 41 driven and rotated by a cutter drive 14 and allowed to freely move in and out by a cutter moving device is placed within the storage recess 11. The rotary cutter 41 is provided with an outer-peripheral-groove cutting bit for cutting reinforcing fibers held within a hard wall, an outer- peripheral-surface cutting bit for cutting a cut plane where a groove is formed, and an intake through which debris excavated is taken into the storage recess 1, and a soil discharging device 10 whereby the excavated debris taken into the storage recess 11 is discharged into a pressure chamber is provided. |
