WIDENING PILE AND INSTALLATION METHOD THEREOF

PROBLEM TO BE SOLVED: To provide a widening pile which can be accomplished easily within a short term without contaminating soil and its construction method.SOLUTION: A widening pipe 1 is configured to be installed on a ground 11 for supporting a building, is formed in the shape of a bottomed columnar body being foldable in a cross-sectional direction and having an internal cavity, and can widen its cross section by being filled internally with fillers. An installation method of the widening pipe 1 includes the steps of: using a supporting frame 7 for pile installation comprised of a steel pipe 8 and a distal end cap 10 mounted removably to a distal end of the steel pipe 8 and inserting the widening pipe 1 to the supporting frame 7 for pile installation; installing the supporting frame 7 for pile installation to which the widening pile 1 has been inserted on the ground 11; separating the steel pipe 8 and the distal end cap 10 of the supporting frame 7 for pile installation and pulling out only the steel pipe 8 to the surface of the ground; and filling the inside of the widening pipe 1 with fillers.