To provide an excavation tool which is efficient by easily discharging a core in an excavation method, and suitable for the excavation method.
In this excavation method in which a cylindrical casing 1 with cutting blades disposed on leading edges is advanced to the tip side in the direction of the axis O and inserted in the ground while the casing is circumferencially turned overall around the axis O, and the core left behind in the casing is discharged to form a drilled hole, a crushing member 4 having crushing blades 5 and 6 disposed in the radial direction with respect to the axis O is fitted to an inner circumferential part on the tip side of the casing 1 in an attachable/detachable manner with an opening part 8 left between the crushing member and the inner circumference of the casing 1, and the drilled hole is formed. After the drilled hole is formed, the crushing member 4 is removed and collected.
HISADA KIMIYA
TANAKA KUNIHIKO
HARA YOSHIKAZU
