| 摘要 |
PROBLEM TO BE SOLVED: To correct the direction by measuring the deviation of a pilot pipe row by drilling in the false direction of an excavation cutter by a position sensing means, directing the eccentric direction so as to receive reverse deviated earth pressure in a pressure-change receiving surface and conducting the drilling. SOLUTION: A target T is disposed at an opening end on the departure shaft side of the hollow pile of a pilot pipe row and a transit C at an opening end on the arrival shaft side. The pilot pipe row P of a first step completely excavated while directly viewing the target T by the transit C is guided while being taken into a screw 4, a screw pipe row 4b and an inserting port 7, and an excavation cutter 3 is rotated and drilled by a pusher arranged to a departure shaft. When the deviation of the pilot pipe row from a laying projecting line L is recognized, the eccentric quantity and eccentric direction of the excavation cutter 3 are measured, drilling is stopped and a deviated earth-pressure receiving surface 8b is directed so as to receive deviated earth pressure perverse to the eccentric direction, and the drilling is performed and the direction is corrected by the eccentric quantity, thus accurately laying a buried pipe. |
