METHOD FOR MEASURING INSTALLATION DEPTH OF OBSERVATION DEVICE IN BORED HOLE

摘要

PROBLEM TO BE SOLVED: To provide an installation method of a casing pipe and a method for measuring installation depth of an observation device in a bored hole, accurately acquiring the installation depth of the observation device, by utilizing a means for detecting the magnetic force which the observation device has, related to a method for installing the observation device comprising a means for detecting a magnetic force in the bored hole.;SOLUTION: When installing the casing pipe in the bored hole, casing pipes with different magnetizing characteristics are combined and installed in the bored hole. The changes in the magnetic force is measured, by a means which moves the observation device within the casing pipe for detecting a magnetic force. The changes in magnetic force is made to correspond to the depth of the casing pipe, and based on the depth of the casing pipe, the installation depth of the observation device which is installed in the bored hole is measured.;COPYRIGHT: (C)2005,JPO&NCIPI