| 摘要 |
PURPOSE: To increase the construction efficiency, by providing a spherical cutter at the front end of a skin plate through a rotary shaft and forming a plurality of intermediately bending means by cylindrical skin plates and skin plates having spherical outer peripheral faces. CONSTITUTION: In the construction of an extremely acute curved line, the ground is cut while rotating a spherical cutter 11 around the rotary shaft 8. At this time, the stretching speed of respective shield jacks 3a, 3b are varied for respective excavation and the intermediately bending jacks 5a, 5b are extended or contracted to bend first and second skin plates 1a, 1b, 1c,... 2a, 2b, 2c,.... After completion of the turning motion, the cutters are gradually returned and the skin plate assembly A is made linear in turn from the nearby side of the cutter 11. In this way, the radius of curvature can be extremely made small and this shield machine can be applied to a tunnel with the same diameter as it is. And also the construction period and cost can be reduced. |
