| 摘要 |
<p>PROBLEM TO BE SOLVED: To enhance operational efficiency during laying that involves pre- reaming. SOLUTION: After a propulsion rod 24 is propelled from a starting shaft 22 to a goal shaft 23, a reamer 27 with a jig 25 attached to its rear is mounted at the end of the propulsion rod 24. The reamer 27 is drawn in toward the starting shaft 22 and pre-reaming is performed. When the pre-reaming is complete, the reamer 27 is pushed into a headway 30. Since the jig 25 is attached to the rear of the reamer 27, resistance from subsoil 21 is reduced and the reamer 27 can easily be pushed back toward the goal shaft 23. Next, a PE pipe 38 is connected to the rear of the reamer 27 and the propulsion rod 24 is drawn in to lay the PE pipe 38 up to the starting shaft 22.</p> |
