| 摘要 |
<p>PROBLEM TO BE SOLVED: To carry out a work to renew a cast iron pipe buried under the ground, into a flexible pipe or a steel pipe, without using an open-cut method. SOLUTION: A starting shaft 2 and a drop shaft 3 are open-cut, a retracting system 4 is set in the drop shaft 3, and a pull rod 5 is inserted from the retracting system 4 to an existing pipe which consists of a cast iron pipe 1. A renewing device A connecting a PE pipe 6 is connected to the pull rod 5. The renewing device A is composed by providing a cutting member 11 having cutter bodies provided at a specific angle in the circumferential direction and plurally in the axial direction; a diameter expanding member having diameter expanding rollers; and a connecting member. The renewing device A is inserted in the cast iron pipe 1, and the inner peripheral surface is cut by the cutter bodies while moving the renewing device A so as to form a cut groove 1b, the inner peripheral surface is cleaved by making the cut groove 1b as the starting point so as to form plural circular arc pieces, the circular arc pieces are pressed in to the natural ground by generating a bending within an elastic limit by the diameter expanding rollers, the PE pipe 6 is pulled in while forming a tunnel surrounded by the natural ground part contacting closely with the circular arc pieces, and the periphery of the PE pipe 6 is armored by plural circular arc pieces.</p> |
