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Technology

Pipeline Replacement: Trenchless Technology

MNB units provide pulling capacity up to 125 tons (depending on the machine type); as a result, they are applicable to replace pipelines from 100 mm to 600 mm, having the length up to 200 meters.

Works for trenchless replacement of a pipeline can be carried out from one pit to another (using UNB-20, MNB-50, MNB-125) or, if necessary due to especially confined space, from the well or the OR-1.5 formwork into the well (MNB-50).

Worn pipeline is destructed in soil and compacted into soil.

Replaced pipeline materials: steel, cast iron, reinforced concrete, ceramics, asbestos

New pipeline materials: polyethylene.

Advantages of trenchless method for pipeline replacement:

  • No risk of damage for adjacent utilities.
  • No disturbances for urban transport or population while the construction is in progress.
  • Pipeline throughput is increased.

PIPELINE REPLACEMENT WORKFLOW
(pit-to-pit method)

Preparation: prepare 2 pits, the working pit and the receiving pit, along the old pit axis.
Working pit sizes: 3 m * 1 m * old pit depth.
Receiving pit size is chosen in accordance with the diameter of a new pipeline.

Driven by the MNB or UNB power unit, bars are pushed along the complete length of the straight-line section (up to 150-200 m).

The polyethylene pipe is welded (the resistance butt welding method is used), and the appropriate knife is put on the pipe. The knife is linked with the unit’s bars.

The power unit pulls the bars and, at the same time, destroys the old pipeline and pulls a new polyethylene pipe.

For works carried out from one well to another, or from the OR-1.5 formwork into the well, threaded-joint polyethylene pipe shells (with the pipe shell length about 0.7 m) are used instead of polyethylene pipes welded as a pipe string.