| 摘要 |
PROBLEM TO BE SOLVED: To efficiently remove segments and to reduce removing steps in demolition work of a deteriorated tunnel or the like. SOLUTION: In an excavator 1 which advances while excavating the periphery of existing segments 2, a plurality of pulling-crushing jacks 42A to 42D equipped with engaging claws 43A to 43D, respectively, are radially arranged from an almost central axis L of a tunnel, which claws are attached to the respective front ends of piston shafts 42a to 42d, for engaging with an external side of the existing segments 2. Then, bolts 40, 40 between segment rings 2A, 2A are cut, and thereafter the engaging claws 43A to 43D of the respective pulling-crushing jacks 42A to 42D are engaged with the external side of the segment ring 2A to be removed, and pulling actions by the pulling-crushing jacks 42A to 42D are simultaneously carried out, thereby crushing the segment ring 2A to be removed.
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