| 摘要 |
PROBLEM TO BE SOLVED: To provide a vertical hole digging method capable of efficiently discharging soil and sand inside a large diameter casing in the vertical hole digging method in which the casing is held through a small diameter adapter for digging. SOLUTION: A vertical hole digging device comprises an adapter 4 having a small diameter, long holding part and capable of connecting a large diameter casing, a main band 5, a main band 5, a rotatably driving device to rotatably drive the main band 5, a thrust cylinder 6 to raise and lower the main band 5, and a sub band 9. After the vertical hole digging device is mounted on a frame 3 movably in lateral direction, the main band 5 on which the holding part of the adapter 4 is held is rotated and lowered while the holding part is passed appropriately from one hand to the other so as to press the casing 2-2 into the ground. Next, after the adapter 4 is separated from the casing 2-2, while the main band 5 is passed from one hand appropriately to the other in association with the sub band 9, the adapter 4 is raised, and then the shaft digging device is moved horizontally so that, for soil exhaustion, a hammer grab 15 can enter directly into the casing 2-2 without passing through the adapter 4.
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