| 摘要 |
PURPOSE:To detect the defective parts in a pipeline laid in the sloped ground easily by inserting a wet cordlike body into the pipeline from above and returning it again upward and detecting the wet parts of said body. CONSTITUTION:A corrugated flexible pipe made of a plastic of a diameter 80mm. pierced beforehand with a hole intentionally at 100m is buried in a 165mm. section between manholes of 1.2m depth below the surface of a road of, for example 4% road gradient, and the position where water enters is detected. A straw cord 1 of about 200m length is prepared and the cord 1 is tied to a steel wire for cable insertion which is beforehand inserted into a flexible pipe 3 through an upper manhole 2A and is pulled in over the entire length up to a lower manhole 2B. Upon lapse of 10min, the cord 1 is pulled up to the upper manhole 2A and the wet position of the cord 1 is measured, whereby it is easily measured that the defective position of the pipeline is near 100m position. |
