| 摘要 |
PURPOSE:To improve the execution performance by installing a through hole and an opening/closing member for opening and closing the through hole at the small circle part of a shield having a potbellied section in joining of the large circle part and the small circle part, when a branched pipe is executed from a stem line tunnel. CONSTITUTION:In the state where the communication hole 21 of a rotary body 20 does not coincide with a through hole 121, a cutter 30 and a copying cutter 31 are driven, and a main line tunnel 70 is excavated to a tumbler-shaped section. Then, after the cutter 30 is brought into stop at a branched pipe execution position, the rotary body 20 is revolved to allow the hole 21 to coincide with the hole 121. Then, a drilling pipe 4 is connected with a drilling machine 40, and inserted into the holes 21 and 121. The pipe 41 is given torque and striking force, and after the excavation up to the reach to a manhole drilled from on the ground, the pipe 41 is pushed outside a shield 10. Further, the rotary body 20 is revolved, and the hole 21 is directed to the vertical direction, and the intrusion of the underground water is averted, and the pipe 41 is left, as branched pipe. Accordingly, execution can be carried out easily and efficiently, and the water sealing performance can be improved, and the direction of a twist drill can be set easily. |
