| 摘要 |
PURPOSE:To obtain different cross sections of excavation by a method in which cutter heads are set eccentrically to the turning center of each turning driver, and a cutting device is provided to the periphery of each cutter in such a way as to lap its tip locuses mutually. CONSTITUTION:Cutter heads 10A and 10B are eccentrically attached to drums 16A and 16B rotatably attached to a shield machine 12, where the drums 10A and 10B are set eccentrically at a fixed distance from the turning centers OA and OB Front excavation is made by rotation of the heads 10A and 10B of the drums l6A and 16B. An actuator 40 such as oil-pressure jack which goes or comes out of the periphery of the heads 10A and 10B is provided to a cutting device 18, and a cutter bit 42 is provided to the front side and tip side of a cutting device 38 appearing or disappearing. Unexcavated portion is excavated by the device 18. Different cross sections of excavated portions can thus be optionally set up. |
