COLUMN REPLACING CONSTRUCTION METHOD AND REPLACING COLUMN

PROBLEM TO BE SOLVED: To provide a replacing column of the substantially same quality when kneaded by an aboveground mixer, by solving the problem in a conventional deep layer mixing processing construction method and a high grade soil construction method. SOLUTION: Boring is advanced while normally rotating a screw auger having an excavation part on the tip. After reaching a replacing bottom part of a column, while delivering a filler including no sediment and aggregate from an auger tip part, the screw auger is pulled up in normal rotation or substantially in no-rotation. After reaching a replacement expected upper end position of the column, delivery of the filler is stopped, and afterwards, the screw auger is pulled up while reversely rotating or normally rotating the screw auger. COPYRIGHT: (C)2007,JPO&INPIT