| 摘要 |
PROBLEM TO BE SOLVED: To provide an underground obstacle survey method for surveying an underground obstacle by forming an investigation hole in a substantially horizontal direction and using a magnetic sensor.SOLUTION: An underground obstacle survey method is configured to drill a hole in a substantially horizontal direction using a casing 1 mounted on a top end part with a cronenbit 8 having a screw part on the rear end part, allow the cronenbit 8 and a manchette tube 6 to be engaged and connected with each other by inserting a polyvinyl chloride resin pipe 2 connecting the manchette tube 6 provided with the screw part on the top end part and formed with many slits 6a around in a drilling direction into the casing 1, pull out the casing 1, inject a filler into the manchette tube 6, fill a gap portion 10 formed between a natural ground part in contact with the casing 1 and the manchette tube 6 with a filler via the plurality of slits 6a of the manchette tube 6, insert a magnetic sensor into the polyvinyl chloride resin pipe 2, and measure magnetic data. |
