| 摘要 |
PROBLEM TO BE SOLVED: To make easy to built the corners of the circumferential wall of a large-diameter tunnel by arranging two cutter heads that drive reciprocatingly near a plane perpendicular to the axial center of a shield using a cutter driver comprises of a parallel link manipulator in the front of the main body of the shield with an L cross section. SOLUTION: A cutter driver 4 is comprised of a parallel link manipulator made up of hydraulic cutter driving cylinders 5A to 5H, pairs of extension actuator, the front end of which is connected to a cutter head 2 in a rotatable manner and the rear end of which is connected to the pressure bulkhead 3 of the shield main body 1 in a rotatable manner. The cutter driving cylinders 5A to 5H are extended and retracted by controlling pressure oil that is connected to and discharged from the cutter head driver 4, the cutter heads 2A, 2B move right and left, and up and down reciprocatingly in a plane perpendicular to the axial core of the shield, and cutter bits 34, 35 bore the natural ground. Thus a tunnel having an L-shape cross section can be excavated at a time and corners of the circumferential wall of a large diameter rectangular tunnel can be built in a short time and accurately. |
