METHOD FOR REPLACING EXISTING OBSOLETE PIPE

摘要

PURPOSE:To replace an existing obsolete pipe with a new pipe without leaving the existing obsolete pipe in earth by a method wherein through injection of air through an air nozzle, a gep is produced, the new pipe is pushed in from the starting shaft side, and through propulsion of the new pipe, the existing pipe is recovered on the arrival shaft side. CONSTITUTION:An air nozzle 5 is mounted in the peripheral wall of an existing pipe 1, running between a starting shaft 2 and an arrival shaft 3, in a manner to extend through the peripheral wall. By blowing air through the air nozzle 5 against earth around the pipe, a gap is produced between the existing obsolete pipe 1 and earth around the pipe. A push force is exerted on a new pipe 9 by means of a jack 8 for pushing a pipe, and a new pipe 9 is pushed from the starting shaft 2 to the arrival shaft 3 along a line. A pushed out existing obsolete pipe 1b is cut on the arrival shaft 3 side by means of a cutter for removal. This method facilitates replacement of the existing obsolete pipe with a new pipe without leaving the existing obsolete pipe in earth.