| 摘要 |
<p>PURPOSE:To replace a buried pipe such as an underground-buried water pipe with a new tube without open cutting by propelling and burying the new tube while expanding the diameter of the previously buried tube by way of gradually pushing a diameter expansion device into the broken previously buried tube with a push bar as a guide. CONSTITUTION:At positions separated from both end parts and others of a road 1 by specified distances, a starting shaft 2 and an arriving shaft 3 are excavated, and to these starting shaft 2 and arriving shaft 3, a previously buried tube 4 is made to face. On the starting shaft 2, a propulsion device 5 is provided, and by pushing a breaking opening device 6 into the previously buried tube by this propulsion device 5, the previously buried tube 4 is broken. The propulsion device 5 is constituted of a jack 7 and a presser plate 8, and by the presser plate 8, the braking cutting device 6 is pushed into the previously buried tube 4 through a push bar 9. Consequently, though cracks are made in a plural number of circular arc pieces on the previously buried tube 4, as a broken and opened part 14 is larger than the inner diameter of the previously buried tube 4 and smaller than the outer diameter, the broken previously buried tube 4 returns to its original outer diameter, fragments neither fall nor are scattered underground.</p> |
