Underground foundation construction material, underground foundation and its construction method

摘要

PROBLEM TO BE SOLVED: To save time and labor for boring a hole for constructing a ground foundation, to reduce a road surface after repairing the hole to make it inconspicuous, to and enable construction at a narrow site. SOLUTION: In this ground foundation, a pipe P inserted into a drilled hole 8 provided in the ground 7 by drilling, directing a pedestal 3 downward, and mortar M filled in the pipe P are pushed down by a core C till it is pushed out of the pipe P through between a hole of the pipe P and the pedestal part 2 pushed and expanded by the core C, so a pole H is set to stand as a lower end part of it is positioned by the mortar M filled between the drilled hole 8 and the pipe P, and a recessed part 6 in the core C reaching a lower end part of the pipe P, with the mortar M filled between the pipe P and the pole H.