| 摘要 |
PURPOSE:To repair existing long pipes by a method in which plural new pipes are penetrated into an existing pipeline from a vertical pit by means of an end- press jack until a given length of the pipes are penetrated, and the new pipes are further penetrated by means of a mid-press jack. CONSTITUTION:New pipes 17a and 17b are orderly inserted into a superannuated existing pipeline 11 by means of an end-press jack 15. When a limit strength to withstand the pressure of the pipe is reached, a mid-press oil-pressure jack 20 is interposed between the new pipes 17e and 18a, and the new pipes 17 and 18 are further penetrated by repeated operations of the jacks 15 and 20. When the top pipe 17a reaches the forward vertical pit 13, the jack 20 is removed out and the new pipe 18 is advanced to complete the construction work. |
