| 摘要 |
PROBLEM TO BE SOLVED: To lay a buried pipe extending to a long distance without problems, without generating troubles by a method wherein when the temperatures of the internal surface of a buried pipe all become a specified temperature, and the descending speed of the temperature becomes a specified value or lower, a resin pipe which is pre-heated to a softened state, is introduced into the buried pipe. SOLUTION: When the internal surface temperature of a buried pipe 1 becomes, e.g. 60 deg.C or lower, a heating is resumed, and the buried pipe 1 is heated until the internal surface temperature of the buried pipe 1 becomes a range of 70±10 deg.C. When the decreasing speed of the internal surface temperature of the buried pipe 1 after the stop of the heating becomes, e.g. 1 deg.C or lower per min, the heating is performed until all the parts of the internal surface reach a range of 70±10 deg.C in the end. After the internal surface of the buried pipe 1 becomes 60 deg.C or higher, a heating fluid such as steam from a boiler vehicle 6 is passed inside in advance, to pre-heat and soften a resin pipe 7 to, e.g. 70 deg.C or higher, preferably closer to 80 deg.C, and the pre-heated and softened resin pipe 7 is tracted by a traction string 8 which is taken up by a taking-up machine 8b through a combining apparatus 8a which is provided at the leading end, and is introduced into the buried pipe 1 from a manhole 2 on the upstream side. |
