| 摘要 |
PROBLEM TO BE SOLVED: To obtain a method for easily and reliably drawing out existing piles, without giving damages to the housing environment of neighboring inhabitants, etc., and also preventing subsequent existing pile cutting operations from becoming difficult due to the slime arising from cutting operations, and to obtain an excavation casing used for this method. SOLUTION: A casing 3 provided with a narrow strip of cutter 8 in a spiral form along its inner bottom circumferential surface in the way that the spiral may reduce its inner diameter as it goes up is inserted into ground while being rotated so as to cover an existing pile 1 to be drawn out. The outer circumference of the existing pile 1 is cut with the spiral cutter 8 located within the casing 3 to reduce the diameter of the existing pile 1, which is then cut off at the point where its diameter has been reduced, and the cut-off pile portion is drawn out. The operations are repeated to finally draw out the entire existing pile 1.
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