| 摘要 |
PROBLEM TO BE SOLVED: To conduct excavation stably in a shield machine excavating a tunnel having a cross section gradually expanded or contracted. SOLUTION: A cutter head 2 having an excavating surface smaller than the cross section of a shield body 1 is arranged to the front section of the shield body 1, and a width expansion-contraction cylinder, in which width can be expanded and contracted, is installed to the shield body 1. A cutter driving device constituting a parallel-link manipulator of eight cutter driving cylinders, in which front end sections are connected to the cutter head 2 while rear end sections are coupled with the shield body 1, is mounted. Cutter expansion- contraction mechanisms 31 capable of extending and shrinking the width of the excavating surfaces by bringing near and separating a pair of left-right split cutters 32 configuring the cutter heads 2 are set up. |
