Technical description of a rehabilitation method
Spirally rolled liners
according to PN-EN 752-5; 13689; ISO 11296-1; 13566-7
1. Method description
The rehabilitation method using spirally rolled lining consists in placing, in the older sewer (or in a manhole), a rolling unit and feeding a special profiled plastic tape. In special cases the tape can be reinforced with steel tape.
The SPR process involves feeding a pressed PVC tape that is spirally introduced into the existing pipeline. Subsequent coils of the profile are connected using locking elements of the tape and the radial space between the rolled profile and the original pipeline is grouted, making an SPR pipe. A sturdy composite pipe is created in that way. It is integrated with the existing pipeline.
2. Liner installation equipment
- sewer cleaning equipment (pressure truck)
- sewer inspection camera
- by-passing unit (pumps, hoses)
- platform truck for transporting the material
- hoisting crane (or container truck with a hoist)
- pumps for feeding grout
- SPR installation unit
- 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 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.
Składowanie i transport na plac budowy
The plastic tape for the spiral pipe is delivered to a storage yard in coils on transport drums. It is delivered from there to the site.
4. Installation of the liner
Depending on local conditions, one of two installation methods can be used. Those are: with a pushing machine or a self-propelled machine. The self-propelled machine has two varieties: Super SPR and Non-Circular SPR. All the systems are presented below.
A. Pushing machine installation process (unmanned operation)
The rolling machine is placed in an existing sewer manhole. The PVC tape is fed from a reel on the ground to the rolling machine. The tape is spirally rolled by the rolling machine and edges of subsequent coils lock, creating a new pipe within the existing one.
B. Self-propelled machine installation process (manned operation)
The installation machine is placed in the existing sewer manhole or anywhere in the existing sewer. The tape is fed to the machine from a middle of a reel designed specially for the process. Then the machine turns and moves inside the original pipe, spirally laying the tape and creating a pipe behind it. Since in this process the pipe is created behind the machine, there is no friction between the SPR material and the original pipe. Therefore, the method is suitable for rehabilitation of long pipeline sections.
1) Super SPR process
The Super SPR process has been designed specially for rehabilitation of large diameter pipelines. It utilizes steel W-shaped or U-shaped reinforcement elements for creating, using the self-propelled machine, composite pipes of high rigidity.
2) Non-Circular SPR technology
The non-circular technology has been designed for rehabilitation of all types of non-circular pipelines. The installation machine consists of a guide frame custom made to the existing pipeline: it matches the shape of the pipeline. A number of rollers move around the frame. The rollers connect the tape and forward the machine. The machine is suitable for installation of both standard and reinforced tape of any cross section.
4.1 Grounting
Before starting the grouting special supports have to be installed inside the helically rolled pipe to prevent it from collapsing during 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 rolled 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 the pipe, so that it does not collapse. It is particularly important when rehabilitating pipes with high diameter and low circumferential rigidity.
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, 13566-7 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.
