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Unconfined Compression Test - NC - OCR

Unconfined Compression Test - NC - OCR

Unconfined Compression Test - NC - OCR


If you don't wanna read it all, read the question at last.
I think I will not find the answer for my question, but I'll try.

You know the SHANSEP method. OK. Now, we have two approach in this one -if we will not perform numerous triaxial tests-

1) Ladd's formula --> cu,OCR / Sigma_V = S x OCR^m
In this formula Ladd gives some S and m values for anyone who want to use them, but for Level C - preliminary studies.

2) Bowles' Figure: In Bowles, 5th edition, Fig. 2.36 He gives B/A vs OCR and B/A*cu,nc = cu,OCR

Now my question: I find Ladd's formula quite unrealistic since he gives a S value and when I try it, it does not fit. Ok. I can deal with it since he oversimplifies it for users.
Bowles is better.
But my question is, when we perform a triaxial test to a soil, which cu we have? NC or OCR? For example we have an OC clay. This clay is taken outside as undisturbed and subjected to triaxial. Now, I think whether the resultant cu is NC or OC is depending on the load level, am i right? I don't know how to understand this.

But my main question is about Unconfined Compression Test. What do we have here? If we put a OC clay to a UC test, do we have cu,OCR ? If so, what is the use of SHANSEP? Okay Shansep have deeper meanings, but how can I use the Bowles' figure?

Question in a pill: How can one understand whether Unconfined Compression Test results is cu,nc or cu,OCR based on the definition of Shansep and Bowles? Is it simple like if your soil is OC then your cu is OC too?

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