# Calculating pressure on an embedded pipe in vertical plane

1. Sep 27, 2011

### CWoodhouse

I have a problem and it consists on placing a square PVC pipe vertically in a trench and surrounding it in concrete, I would like to know how would I calculate the sufficient wall thickness of this pipe and the maximum depth of the trench etc before the pipe would yield to the surrounding pressure of the concrete. I am not sure how the pressure will be distributed within the walls of the trench and how much of concrete head pressure will be acting on the pipe.

Can anyone help?

2. Sep 27, 2011

### Travis_King

Does the pvc pipe have to be empty of concrete to the bottom? If you allow the bottom to fill up some with concrete, you wont have to worry too much about it.

3. Sep 27, 2011

### CWoodhouse

Yes the pipe would need to be sealed, causing a pressure difference.

4. Sep 29, 2011

### RocketSci5KN

Option A: use a cylindrical 'pipe', which is much easier to find, cheaper, and will handle pressures much better.

Option B: Fill either 'pipe' with any fluid having a density at or above the concrete, such as something similar to drillers mud, and pump out later. That way, no differential pressures.

Option C: Obtain the working pressure for the PVC schedule proposed, and derate it by a factor of 3 or so since pipes perform worse for external pressures than internal. Calculate the concrete pressure at the bottom, knowing its density is about 2.4gm/cc. Limit concrete height to what would give you 1/3 of the internal pipe rating.

Option D: combine option C with a water fill to get some internal pressure.