Critical State Soil Mechanics

[soman703]

Hello everyone,
I have a question,

For critical State soil mechanics.
Whats the status of critical state line? Is it always above or below the NCL?
Whats the reason for its being above or below?

If Initial condiiton of a volume of a granular material is above Critical state line and the material
is then sheared in undrained conditions, the value of P' at failure will be lower than the initial one.
Whats the reason behind it?

What does critical state line defines? Does it define relationship between mean effective stress P',
Deviatoric stress q and specific volume V which identifies peak strength of a granular material.
If not this what things can we conclude from critical state soil mechanics line?


Critical state line defines relationship between mean effective stress P' , deviatoric stress q and specific volume V
which identifies condition at which material can be sheared without changes in volume and in shearing stress.

Whats the reason behind critical state line being independent of state of material
(whether its loose, over consolidated or normally consolidated)??

 

[fattdad]

You are actually asking a few questions and provide no context. In other words, why should I take the time to provide any answers when I don't know the end game?

f-d

ípapß gordo ainÆt no madre flaca!

 

[BigH]

Pick up a copy of Malcolm Bolton's "A Guide to Soil Mechanics" or David Muir Wood's "Soil Behaviour and Critical State Soil Mechanics". Study them, then repost if needed.

 

[ATSE]

Dr. Paul Mayne from GIT has produced some CSSM presentations that can be found with the search words "Critical State Soil Mechanics for Dummies" or "Simplified Critical State Soil Mechanics."
A lot easier reading than the Wood or Schofield texts.
Both Plaxis and FLAC haves technical discussions on the practical use CSSM in relation to MCC and Soft Soil models (based on CSSM).