| 摘要 |
PROBLEM TO BE SOLVED: To provide a circular shape holding device which smoothly carries out repositioning and is high in reliability. SOLUTION: The circular shape holding device includes a lateral pair of arcuate long-sized support frames 53a, 53b hinge-connected with a pin 52 at the bottom of an inner form M assembled in ring shape, and extending to the upper part of the inner form; a longitudinal pair of arcuate short-sized support frames 56a, 56b with base ends connected to the upper ends of the long-sized support frames with first pins 54 and with the tip side longitudinally overlapped at the top of the inner form and connectable with second pins 55 at two circumferential parts; two stopper pins 60 respectively located above the connected part with the first pin to further pin-connect both support frames; two push-up jacks 66a, 66b pushing up the two short-sized support frames individually; two extension jacks 67a, 67b extending the two long-sized support frames individually; and a movable frame 61 movable in the excavating direction of a tunnel while supporting the heads of the push-up jacks and extension jacks. COPYRIGHT: (C)2011,JPO&INPIT |
