| 摘要 |
PROBLEM TO BE SOLVED: To provide an excavation method for a shaft and a device therefor, allowing a hole-wall curing member to be mounted on the inner surface of the excavated shaft and enabling the placing of bottom base concrete and the removal of an excavating device without being obstructed by the excavating device. SOLUTION: The excavation method comprises: an excavating process composed of the preceding excavation by means of a casing (4) and the widening excavation by means of an excavating wing (5); a hole-wall curing member mounting process wherein the hole-wall curing member (2) is mounted on a wall surface after the excavation to a fixed depth; and a bottom base concrete placing process wherein a bottom base (20) is placed after the completion of the excavation to a prescribed depth. A cutter (5c) located on the outermost periphery of the excavating wing (5) for performing the widening excavation is constituted in an extendable manner, and the retraction of the outer periphery of the end thereof permits the excavating wing (5) to be drawn up for the purpose of conducting the placing of the bottom base concrete and the removal operation of the excavating device.
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