WORKING METHOD BY WORKER DURING TUNNEL EXCAVATION

PROBLEM TO BE SOLVED: To provide a shield machine provided with a shield cylinder 1 and an excavation unit 2 and a ring body 16 fixed at the inner periphery of a front part of the shield cylinder, providing the excavation unit with a bulkhead 21 fitted into the ring body internally, and having a cutter head 22 extending and contracting freely in the radial direction and supported on the bulkhead 21 and a driving unit 23 for driving the cutter head on a rear surface of the bulkhead to allow a worker to enter a space 25 between the cutter head and the bulkhead and work safely during excavation by use of this shield machine. SOLUTION: In this working method, the shield cylinder 1 is made to advance up to a working face while fixation of the bulkhead 21 on the ring body 16 is released to store the cutter head 22 in the ring body 16, next the driving unit 23 is removed from the bulkhead 21 to insert an injection pipe 5 into the working face through the bulkhead 21 in this condition in order to pour chemical into the ground in front of the working face and cut off water on the working face, and then the worker enters the space 25 between the cutter head 22 and the bulkhead 21. COPYRIGHT: (C)2010,JPO&INPIT