# Variation of (pore pressure) due to consolidation

• tzx9633

## Homework Statement

In the last picture , we can see that at time between 0 and infinity , the variation of pore pressure across depth is parabolic curve , why is it so ?

## The Attempt at a Solution

I think it's incorrect . I think it should be linearly decrease with depth . This is because the top part will receive max force from the applied force . The influnece of force decrease with the depth

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## The Attempt at a Solution

I think it's incorrect . I think it should be linearly decrease with depth . This is because the top part will receive max force from the applied force . The influnece of force decrease with the depth
I'm not completely clear what you are saying here. What are you conceiving as the source of the applied force? You have two components: loading from the solid portion of the soil, sediment or rock and loading from the fluid content of the pore space. In an equilibrium situation the solid load is supported by the soil/rock and the fluid load by the pore space content. Both of these are proportional to depth and increase with depth, not decrease, as you appear to suggest.

One of your diagrams looks like the classic model from Terzaghi and Peck's classic paper published 50+ years ago, which describes a non-equilibrium condition and relates to the parabolic curve you have been asked to account for.

jim mcnamara
I'm not completely clear what you are saying here. What are you conceiving as the source of the applied force? You have two components: loading from the solid portion of the soil, sediment or rock and loading from the fluid content of the pore space. In an equilibrium situation the solid load is supported by the soil/rock and the fluid load by the pore space content. Both of these are proportional to depth and increase with depth, not decrease, as you appear to suggest.

One of your diagrams looks like the classic model from Terzaghi and Peck's classic paper published 50+ years ago, which describes a non-equilibrium condition and relates to the parabolic curve you have been asked to account for.
if it's increasign down the depth , why the graph of pore pressure has parabolic shape ? Sholdnt it has a straight line graph ?

I'm not completely clear what you are saying here. What are you conceiving as the source of the applied force? You have two components: loading from the solid portion of the soil, sediment or rock and loading from the fluid content of the pore space. In an equilibrium situation the solid load is supported by the soil/rock and the fluid load by the pore space content. Both of these are proportional to depth and increase with depth, not decrease, as you appear to suggest.

One of your diagrams looks like the classic model from Terzaghi and Peck's classic paper published 50+ years ago, which describes a non-equilibrium condition and relates to the parabolic curve you have been asked to account for.
Is there anything wrong with the notes ? If so , then , why the graph has parabolic shape ?

I need to take a thorough look at all the material. I'll aim to get back to you within 24hours. It would be helpful to know what context this is in. Are you considering soils (which I know little about) or sediments (where I have a pretty solid grounding)?

I need to take a thorough look at all the material. I'll aim to get back to you within 24hours. It would be helpful to know what context this is in. Are you considering soils (which I know little about) or sediments (where I have a pretty solid grounding)?
Hi , it the soil . Do you have any updates now ?