| 摘要 |
<p>PURPOSE:To make it possible to replace piping without excavating the surface soil of buried spots by outer fitting and inserting a large sheath-like pipe with a minor diameter larger than an outer diameter of an old pipe in the old pipe underground and pushing out the old pipe in the large sheath-like pipe to insert a new pipe. CONSTITUTION:A large sheath-like pipe 4 with a minor diameter larger than an outer diameter of an old pipe 3 is successively connected to outer-fit and insert in all the old pipe 3 underground 2 from one pit, and the soil around the old pipe 3 is also involved into the large sheath-like pipe 4 together with the old pipe 3. After that, the rear end of the old pipe 3 in the large sheath-like pipe 4 is pushed out, and a new pipe 10 is inserted into a clearance made by eliminating the old pipe 3 in the large sheath-like pipe 4. While the large sheath- like pipe 4 remains underground 2, the old pipe 3 and cutting off soil are col lected by the other pit; as the result, the old pipe 3 is completely replaced by the new pipe 10 without leaving the old pipe 3 underground 2.</p> |
