METHOD FOR FORMING COLUMNAR BODY

PROBLEM TO BE SOLVED: To reduce a variation in the strength of a columnar body due to the difference of grounds while securing the high strength of the columnar body. SOLUTION: This method for forming a columnar body in a ground includes a press-fitting step of press-fitting a spiral rod 1 into the ground while rotating in such a manner that the conveying direction of a conveying screw 2 is aligned with the press-fitting direction of the spiral rod 1 and conveying a bulk load 4 containing a hydraulic material in the press-fitting direction by the conveying screw 2 for supplying the bulk load into the ground and a raising step of raising the spiral rod 1 while rotating the spiral rod in the same direction as in the press-fitting step. In the raising step, the bulk load 4 is supplied into a drilled hole by the conveying screw 2, and water is supplied into the drilled hole through a liquid supply passage 3 to form the columnar body in the ground. The supplied amount of water in the raising step is set equal to or higher than the amount at which the hydraulic material in the columnar body portion 9a defined by the outline of the spiral rod 1 when the press-fitting step is completed is completely hydrated. COPYRIGHT: (C)2010,JPO&INPIT