Hi, When concrete is poured into

[aj_k]

Hi,

When concrete is poured into the pile(for a fully soil displacement pile), in its fresh concrete stage, does the horizontal stress from concrete at a particular depth which is acting towards the soil will be less than the vertical depth at that level? If so, how to determine the horizontal stress from the vertical stress?
Or the horizontal stress acting towards the soil will be equal to vertical stress?

 

[oldestguy]

Assume the concrete goes into a pipe or other casing. Then the horizontal soil stress is only a function of what was developed during driving. Has no relation to the stresses in concrete when poured (placed).

 

[hokie66]

Not sure why you want to know this, but the concrete is fluid, so the pressure should be the same in all directions. Is this a bored pile? I assume by your question it is not cased, so it could be a simple bored pile in soil which is self supporting, or it could be a displacement pile using other methods, perhaps a grout injected pile.

 

[HTURKAK]

Displacement piles are driven piles which displaces the soil during pile driving operation. For your case,not sure but i understand, the circular pipe with closed tip driven and pulled out and the hole is concreted.. is this true? or you mean bored pile ?


Full hydrostatic pressure will develop in case of self compacting concrete. The lateral concrete pressure depends on several factors
( rate of placement, slump , temperature...)

For more details ; you may look to ACI 347 Guide to Formwork for Concrete and DIN 18218 Frischbetondruck auf lotrechte Schalungen.

 

[aj_k]

Thank you all for your reply.
The pile is a full soil displacement pile without a casing.
Sorry, there was a mistake in my question that I asked before.
While the concrete is in the silo, before pouring it, how to calculate the horizontal stress of concrete acting towards the silo wall (pouring pipe) from the vertical stress?

 

[HTURKAK]

Do you mean tremie pipe? which is a watertight pipe, having a conical hopper at its upper end ..

If this is the case, the pressure which will develop can be calculated with Bernoulli eq. Essentially hydrostatic pressure of fresh concrete. P =γ*H

 

[aj_k]

Thank you HTURKAK for your reply.
Yes, I mean the tremie pipe.
The equation which you mentioned is for calculating the vertical stress, P =γ*H
But will the horizontal stress acting towards the wall of the tremie pipe will be the same as vertical?

 

[r13]

The fresh concrete is fluid-alike, the pressure is equal in all directions.

 

[aj_k]

Thank you for your reply.
But concrete is a non-Newtonian fluid, so the horizontal stress will be less than the vertical, but with which factor will it be reduced?
I mean with a k factor of some value.