| 摘要 |
PURPOSE:To remarkably improve profitability of the execution by withdrawing expensive main equipments from a vertical shield machine, and repeatedly utilizing them. CONSTITUTION:In the lower end part of a shaft 2 built vertically downward with a closed type mud water pressurizing vertical shield machine 1, the cutter head 3 of the vertical shield machine 1 is contracted in diameter, and retreated up to a first chamber 4 inside the shield main body. Mud water in the first chamber 4 is replaced by fresh water, a diver is entered into a second chamber 8 between a first partition wall 5 and a second partition wall 6, then the second chamber 8 is filled by fresh water, and pressurized up to the same pressure as that of the first chamber 4. Hereafter, the diver opens the hatch 5a of the first partition wall 5 and enters the first chamber 4, disassembles the cutter head 3 and the other main equipments to be withdrawn, and brings them into the second chamber 8. After completing the work of disassembly and withdrawal, the diver returns into the second chamber 8, fully closes the hatch 5a of the first partition wall 5, and then reduces the pressure in the second chamber 8 and returns to the shaft 2 side. |
