| 摘要 |
PROBLEM TO BE SOLVED: To provide a ground improvement work method which can save material cost by reducing the volume of a hardener used, and can save waste disposal cost and protect the earth environment from adverse effects by reducing the volume of sludge produced. SOLUTION: After excavating ground to a certain depth with a bit 2 provided at the end of a rod 1, super high-pressure jet water 6 is spouted through a nozzle 3 provided at a side of the rod end. While the rod 1 is rotated to cut ground around it, the cut soil is replaced with a hardener. After the cutting, the rod 1 is lifted to a position where the next improved ground layer will be formed, and the replaced hardener hardens to form a first improved ground layer 11a. Next, super high-pressure jet water 6 is spouted at the position where the rod 1 has been lifted, to form a second improved ground layer 11b like the first layer. Thereafter the rod 1 is lifted stage by stage at a predetermined interval to finally construct a plurality of discontinuous improved ground layers 11 in the vertical direction.
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