pipe installation
pipe installation
(OP)
We have a tunnel a little over 12’ in diameter in which 2 60” force mains are going to be run. The tunnel will be about 4000’ long. I believe the pipe is going to be rfp or possibly hdpe. I have little experience in this but I have to come up with some installation options to put on our bid drawings. I have been hearing about 2 methods that are probably going to be used….either sliding or carrying the pipe. The tunnel is fairly straight a slight vertical curve will be present. As of now the tunnel is about 40’ deep with 30’ shafts. Can someone give me a rundown of the 2 installation methods….if the sliding method is used do they just fill the invert and push the pipe along the concrete?….if the pipe is carried in there will not be a lot of room for the second pipe to be worked on…how will the connection be made?…….what kind of problem will I have grouting in the pipe after installation….is the grouting needed?
Any infomation on the pipe or installation would be helpful…thanks
Any infomation on the pipe or installation would be helpful…thanks





RE: pipe installation
Grouting will most likely be needed, for thrust resistance alone, but may also be required for lateral support at that vertical curve.
With small diameter pipes, connection is by fiberglass overlay, but I would guess there are couplings inside the overlay with 60" diameter.
Remember: The Chinese ideogram for “crisis” is comprised of the characters for “danger” and “opportunity.”
-Steve
RE: pipe installation
Fibreglass pipes could be pushed along with jacks from the back. Use side guides with lead-ins at intervals for each pipeline to avoid buckling. Again use skids and light railtrack to reduce pushing load and avoid damage.
I would leave the railtrack there.
RE: pipe installation
RE: pipe installation
RE: pipe installation
Once the pipe has been positioned they will grout around most of the pipe circumference I assume this will provide the restraint that would be required during operation.
Is there a particular type of grout typically used in this application?
RE: pipe installation
RE: pipe installation
RE: pipe installation
Pipeline liners are installed routinely up to 500m long by pulling from one end after the liner has been compressed. It is run through rollers to reduce the outside diameter. The creeep relaxation properties allow it to regain its original dimension so it becomes a tight fit in the steel liner.
In your situation if you were to pull from one end and use rollers to push from the other the line could be readily installed. Just beware that the number of welds per day on a pipe this size would be about one very 2 hours. You need to allw the weld to cool to gain strength. So a strategy of welding lengths at the launch site and just make joining welds will speed things up.
The problem with the legacy materials of DI and FRP is what do you do with a leak at the rubber ring joint?
RE: pipe installation