| 摘要 |
PROBLEM TO BE SOLVED: To change an overage pipe with a new pipe without leaving the deteriorated pipe in the ground and without excavating the ground surface even in the case of a narrow underground pipe having a problem from the point of environmental standard such as a lead pipe. SOLUTION: Vertical shafts 2a, 2b and 2c are excavated from the ground surface at a start end 1a and a terminal 1b of a straight pipe part of an embedded pipe 1. The axial directional force is applied to the straight pipe part of the embedded pipe from the vertical shaft 2a and 2b so as to extrude the embedded pipe toward the other vertical shaft 2c. A projected part 1d of the embedded pipe 1 projected into the vertical shaft 2c is cut in order, and while a new pipe is inserted by a length corresponding to the projected quantity, while following the embedded pipe 2 extruded from the vertical shaft 2a and 2b. The embedded pipe is extruded to the vertical shaft 2c through the inserted new pipe 4, and the embedded pipe is thereby changed with the new pipe without excavating the ground surface.
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