Hole warping measuring method null at time of

摘要

PROBLEM TO BE SOLVED: To prevent the breakage of an adjacent hole in re-excavation by inserting the position detecting sensor for an excavating bit part under drilling into a drilled adjacent hole, and estimating the positional relation between the hole under drilling and the adjacent hole. ;SOLUTION: An excavating sound of an excavating bit 3 is generally differed according to the property of the ground or the presence of an obstruction, but it is preliminarily judged by a preceding examination, and the excavating sound is made to substantially constant excavating sound within the same or approximate ground quality. Thus, the stronger the excavating sound, the nearer the excavating bit 3, and it is detected by a receiving sensor 11 to estimate the positional relation of the excavating bit 3 with an adjacent hole 2, and the hole curve of an excavated hole 1 is measured. At that time, the hole curve can be precisely measured from the estimation result of the positional relation of the excavating bit 3 to each adjacent hole 2, and the hole curve under drilling can be relatively easily measured. Thus, the re-excavation is early performed as occasion demands, whereby a bad effect on the adjacent hole 2 or the breakage thereof can be prevented, and an excessive excavating work can be also avoided to improve the workability.;COPYRIGHT: (C)1998,JPO