BORING APPARATUS AND METHOD OF BORING HOLE IN CAST-IN-PLACE PILE

摘要

PROBLEM TO BE SOLVED: To provide a boring apparatus which eliminates disposal of surplus soil to curtails costs, and ensures concrete adhesion to a bored wall, and to provide a method of boring a hole in a cast-in-place pile.;SOLUTION: The boring apparatus A has: a driving shaft 1 having a front end 1a and a rear end 1b located on the same axis 1c, and having a first decentered portion 1d and a second decentered portion 1e arranged at intermediate locations; a rotor head 2 unrotatably supported by the front end 1a; a plurality of cone rotors 3 rotatably supported by the rotor head 2; a first rotor 4 rotatably arranged on the first decentered portion 1d; and a second decentered rotor 5 rotatably arranged on the second decentered portion 1e. The first decentered portion 1d and the second decentered portion 1e have the same dimension e, but they are decentered in mutually different locations. The cone rotors 3 are arranged such that the axes 3d thereof cross each other at a location O on an extension of the axis 1c, and that distances from the core 1c become larger at locations more separate from the crossing location O and closer to the rotor head 2. Further the first rotor 4 and the second rotor 5 each have screw grooves 7 formed in a peripheral surface thereof.;COPYRIGHT: (C)2009,JPO&INPIT