DRILLED HOLE PRECISION CORRECTING METHOD AND DRILLED HOLE PRECISION CORRECTING DEVICE

摘要

PROBLEM TO BE SOLVED: To form an objective drilled hole by simply making a correction even when a plurality of drilling shafts are twisted as a whole during an excavation.;SOLUTION: A plurality of drilling shafts 1 aligned in a line in the lateral direction are divided into the drilling shafts 1 rotated in one direction and the drilling shafts 1 rotated in the opposite direction. When the tip sections of the drilling shafts 1 are twisted as a whole and rotated and drifted as a whole on the plan view from the normal position in drilling the ground 2 while the drilling shafts 1 aligned in a line in the lateral direction are rotated, the revolving speed of the drilling shaft 1 giving the rotating force in the twisting direction among the drilling shafts 1 is reduced for drilling, thereby the drilling shafts 1 are rotated and returned in the opposite direction to the twisting direction as a whole.;COPYRIGHT: (C)2002,JPO