| 摘要 |
<p>PURPOSE: To enable a new pipe to be pushed in smoothly even without shock such as strike and the like by boring the outer periphery of the old pipe in advance with a sleeve pipe and then pushing in the new pipe along the old pipe. CONSTITUTION: A set-out pit 11 and an arrival pit 12 are dug at the two end portions of an old pipe 10 to be substituted. A sleeve pipe 1 with a sleeve pipe bit 7 provided at the distal end and a water supply pipe 4 arranged between an outer pipe 2 and an inner pipe 3 is put to cover the outer periphery of the old pipe 10 from the set-out pit 11. The sleeve pipe 1 is rotated and fed along the old pipe 10 by a boring machine 15 while pressured water is jetted from the distal end of the water supply pipe 4. When the sleeve pipe bit 7 arrives at the arrival pit 12, segments of a new pipe 16 are pushed in sequentially via a swivel joint 13 from the arrival pit 12 so that the sleeve pipe 1 and the old pipe 10 retreat. The pushed out sleeve pipe 1 and old pipe 10 are reclaimed from the set-out pit 11.</p> |
