Trenchless pipe installation - GIF

[ToolTalkBot]

Trenchless pipe installation.





Previously:

Trenchless pipe and utility line installation

[hemmjo]

How is that pipe installation?

[Karl_H]

How is that pipe installation?

If you question was rhetorical - stop here, but note that the pipe being split was installed trenchless since it is laying above th ground.

If you were asking a real question - a stiff but bendable pipe is fitted into the female end of the splitter and is pulled through the void created by splitting the old pipe.

[desbromilow]

be nice to have the split at the bottom so the remains of the old pipe could double as armour for the new pipe. it would probably cause "lift" though

[hemmjo]

I do notice that the pulling hear is designed for a pipe to follow it through the ground. A lot of pipe was replaced around here using a similar concept, but the new pipe was size ti fit into the old. I see two situations in the video..

#1 the pipe is buried less than 1 pipe diameter under sand which totally collapses as the cutting head is pulled through. We have no idea how long that pipe runs under the sand. The set up appears to be staged as the pipe daylights into a wood box set into soft sand. That is a big pulling head. The bend radius for a pipe that size to large fot the pipe to follow i into that box.

#2 we see a section pf pipe resting on pallets and connected what I assume is the pulling machine. If that pipe was in fact buried in any number common of substrates, those jagged edges created by the cutter would not be able to flay away like that and would possibly even be pressed back onto place with the jagged edges slicing into the new plastic pipe.

Interesting concept, I just have questions about real world use.

[Frank S]

I do notice that the pulling hear is designed for a pipe to follow it through the ground. A lot of pipe was replaced around here using a similar concept, but the new pipe was size ti fit into the old. I see two situations in the video..

#1 the pipe is buried less than 1 pipe diameter under sand which totally collapses as the cutting head is pulled through. We have no idea how long that pipe runs under the sand. The set up appears to be staged as the pipe daylights into a wood box set into soft sand. That is a big pulling head. The bend radius for a pipe that size to large fot the pipe to follow i into that box.

#2 we see a section pf pipe resting on pallets and connected what I assume is the pulling machine. If that pipe was in fact buried in any number common of substrates, those jagged edges created by the cutter would not be able to flay away like that and would possibly even be pressed back onto place with the jagged edges slicing into the new plastic pipe.

Interesting concept, I just have questions about real world use.

As you have mentioned there are a few questions about the operation.
To me this appears to be a demonstration or a test to prove or disprove the possibility to replace a section of an old pipeline which probably runs under an existing structure such as a building or a road most likely a road. In which case would be buried several feet below the surface and yes, the substrate the pipeline would be buried in would be restrictive. I doubt that it could be substantial enough to cause the split pipe to collapse back in on the new pipe being pulled through with enough force to damage it however you are correct in that the severed edges would probably not flyaway as freely as the demonstration suggests.
My question is what tonnage of force would be required to split spread and pull a new pipeline through the old pipe given that it would be as we believe would be buried several feet below the surface.
I do a lot of work for a contractor who regularly pulls pipe under roads after boring. He has tried to pull 6" pipes through a bore that was not several inches larger than the pipe A 6" pipe cannot easily be pulled through even a 7" bore. He has tried to use expanders that I have made for him his machines have 100 tons of pulling power but trying to pull an expander of 8" in diameter through a 7" bore hole or 60 feet in length while dragging a 6" pipe which is close to 7" OD requires nearly all of the machine's capacity. Having to start and stop to remove the drill pipe sections is where the problems arrize

[Karl_H]

My son had this done in Philly. They dug a 2x2 hole through the basement concrete where the cast iron left the building, and another hole 60-70 feet away where the cast iron met the city line.
This was possible because the entire line was still patent, though with lots of damage and places where collapse was imminent.
Here is an animation of the process:

[hemmjo]

At 32 seconds, " the new polyethylene pipe is rated to last 50 years" 50 years is not really a very line time. I used to think 30 years was old, but now I am 77, 50 years is just the blink of an eye!!!

[Floradawg]

I think they mean at a minimum, 50 years. It seems to me it could last much longer.

This is an interesting explanation for why time speeds up as you age.

[Frank S]

I think they mean at a minimum, 50 years. It seems to me it could last much longer.

This is an interesting explanation for why time speeds up as you age.

Never ask a physicist a philosophical question about time if you are not prepared for the answer.