| 摘要 |
PURPOSE:To keep the pressure balance of a facing constant, and to prevent the breaking of the facing by providing a cutter face with a means forming both side ends of a slit to an arcuate surface or leveling the facing in which an arcuate protrusion is projected to the front of the cutter face. CONSTITUTION:Both side ends of slits 6 extending in the radial direction formed to both side sections of the cutter spokes 3 of a cutter face 5 are shaped to arcuate surfaces 6a with smooth curved surfaces constituting a means leveling a facing. The facing cut by the arcuate surfaces 6a is pressed down and leveled by revolving torque and jack thrust while rolling in clay and particulates in muddy water on excavation. The facing roughened by digging is given instantaneously self-supporting properties through consolidation, and an impermeable layer is shaped and water pressure is worked effectively. Arcuate protrusions are projected to the cutter face 5, or the arcuate surfaces and the arcuate protrusions may be combined. |
