DRILLING METHOD FOR PILE PULL-OUT CONSTRUCTION METHOD AND CASING FOR PILE PULL-OUT CONSTRUCTION METHOD

摘要

PROBLEM TO BE SOLVED: To make efficient drilling possible even in case of a buried pile being bent by bending a casing along the buried pile to carry out drilling action in drilling a hole. ;SOLUTION: A casing 1 is erected on a buried pile to be pulled out. Cylindrical bodies 4, 5 are rotated by a rotatory-driving part 2, and when a cylindrical drilling body 6 is rotated through a connected universal joint 8, the drilling body 6 excavates into the ground along with the descent of the rotatory-driving part 2. At this time, mixed liquid of high pressure air and water is supplied into a drilling position at the lower end of the drilling body 6 from a connecting passage 9. In case the buried pile is bent halfway, when the drilling body 6 excavating into the ground reaches the bent part of the buried pile, the drilling body 6 is freely bent by the universal joint 8. The drilling body 6 is thereby guided along the side face of the bent part small in drilling resistance so as to excavate in a bent state. Drilling can therefore be performed without hindrance even in case of the buried pile being bent.;COPYRIGHT: (C)1998,JPO