Segmental pipe sliplining

Technical description of a rehabilitation method
Segmental pipe sliplining
according to PN-EN 752-5; 13689; ISO 11296-1; 13566-5

1. Method description

The rehabilitation method using segmental pipe sliplining consists in inserting short pipe segments inside the old pipeline. Depending on the type of the network and pipeline being rehabilitated, the liner is introduced through an existing manhole or an excavated insertion point.
The shape of the lining segments match the existing pipeline cross-section: they can have a circular and non-circular cross-section.

2. Line installation equipment

  • sewer cleaning equipment (pressure truck)
  • sewer inspection camera
  • pulling machine (pipe puller)
  • by-passing unit (pumps, hoses)
  • platform truck for transportation of the liner (segments)
  • hoisting crane (or container truck with a hoist)
  • pumps for feeding grout
  • sewer ventilation unit
  • pneumatic fretsaw
  • pneumatic jigsaw
  • testing equipment

3. Preparation to installation 

Assessment of the sewer’s technical condition

Before starting rehabilitation, the pipeline is cleaned using a hydrodynamic sewer cleaning unit mounted on a truck. Then the pipeline is inspected using a remotely controlled camera. The video footage is used for preparing a detailed digital report on the pipeline’s technical condition. The report is a base for classifying the sewer’s technical condition. 

Choice of the rehabilitation method

The rehabilitation method depends on the technical condition class and damage degree. After the assessment of the sewer’s technical condition, geodetic data have to be analyzed, including ground water level compared to the base of the sewer, motor traffic in the area, and other parameters that impact parameters of the selected liner.

Storage and transport to the site

Segmental liner is delivered to a storage yard and supplied to the site in small batches.

4. Installation of the liner

Individual rehabilitation liner segments are inserted into the sewer through existing manholes (in case of segments up to 0.5 m long and DN 600 mm in diameter) or through excavated insertion points, using a hoisting device matching the weight of the segments.

Afterwards, the segments are moved to the installation point manually, using a slide or a special trolley. They are connected using a seal placed in a socket. They should be aligned with the center of the existing pipeline. 
Liner segments smaller than 500 mm can be connected manually using special equipment. With larger sizes manual hoists, levers, and presses have to be used. During connection operations the segments’ connection surfaces should be protected against damage. Do not apply force to any point or small area of a bare segment end.

Before connecting two segments, mark the required spigot insertion depth on the bare end of the section. Only complete insertion of the spigot guarantees secure and tight connection. Sealing elements in the sockets are subject to high pressure forces, so mechanical devices should be used for connecting segments. 

Before making a connection, every segment should be properly prepared: the spigot and socket should be cleaned, dried and degreased, especially in the seal area. In case of glued connections the adhesive should be applied with a proper tool, e.g. with a brush, and its excess can be wiped with a cloth or removed with a scraper. The reaction time depends on the type of adhesive used and the ambient temperature. In every case the instructions of the adhesive manufacturer have to be observed.

4.1. Connecting house drains to man-accessible sewers

Using a pneumatic fretsaw, make an opening in the point where the house drain is to be connected to the segmental liner. Then, using a pneumatic jigsaw, cut an opening matching the inner diameter of the house drain pipe. Then, make:

  • a packer 1000 mm long in the house drain,
  • connect the packer with the segmental liner using lamination method.

The lamination surfaces should be dry, degreased and clean. The operations should be performed with ambient temperature not lower than 10oC and humidity below 70% (for that purpose sewer ventilation units should be used).

4.2. Grouting

Grouting consists of „n” stages and is done at sections between individual manholes. At the lower manhole, seal the space between the existing sewer and the segmental liner, at levels 1/n; 1/n +1/n;... install check tubes and in the top point – a stub pipe for feeding the grout. In the top point of the upper manhole, install a breather pipe that ensures free bleeding of air and a stub pipe for feeding the grout.

Grout has to be injected with a pressure that does not cause exceeding maximum buckling stress set for pipe, so that it does not collapse. It is particularly important when rehabilitating pipes with high diameter and low circumferential rigidity. While grouting the space between the pipes, place spacers inside the segmental lining preventing its distortion in result of the grout’s pressure. 

5. Inspection

5.1. TV Inspection

After the installation and opening connections, acceptance TV inspection (including VHS or CD recording) is carried out. Inspection report is also prepared.

5.2. Tests

According to PN-EN ISO 11296-1, 13566-5 and PN-EN 1610

6. Correction of flaws

Flaws are corrected using a robot controlled via a camera or / and inserting and gluing short pipe sections.