| 摘要 |
<p>PROBLEM TO BE SOLVED: To pull inner pipes into an underground installation object, which has an inner space into which a number of the inner pipes can be puled in neatly arranged states. SOLUTION: A concrete trough 1 having a flat bottom is used as an underground installation object. First, a 1st inner pipe 3 is pulled into the trough 1. After inner pipes 3 subsequent to a second pipe have been pulled into the trough 1, each pipe is pulled by a tension of not less than 10 kgf, while the pipe is made to contact the 1st inner pipe already installed. The zigzag form of the 1st inner pipe is reformed, and the 1st inner pipe is made straight. The straight states of the 2nd and subsequent inner pipes can also be maintained through mutual interferences of the respective pipes.</p> |
