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Soil Classification


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#1 Dano_PE

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Posted 27 March 2012 - 11:31 PM

Data:
TOTAL percent retained: Sieve 4-4%, Sieve 8-11%, Sieve 16-21%, Sieve 30-22%, Sieve 50-24%, Sieve 100-17%, Dust pan-1%.
If you total all of the TOTAL percentages you get 100.

CUMULATIVE percent retained data: Sieve 4-4%, Sieve 8-15%, Sieve 16-36%, Sieve 30-58%, Sieve 50-82%, Sieve 100-99%.
If you total all of CUMULATIVE data you get 294.

My question is which set of data do I use to classify the soil for USCS and AASHTO? Is it the TOTAL or CUMULATIVE percent retained (or passing depending on which data is provided). I know I need the cumulative data if I want to calc a fineness modulus(unreated to soil classification) but I am unclear on which data set to use for classification.
Please help. I have pulled out many hairs over this as you can see!

#2 evrick1952

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Posted 28 March 2012 - 04:07 PM

Depends on how they state the problem.........

#3 Jayman_PE

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Posted 28 March 2012 - 04:08 PM

For USCS you need % passing for almost everything, except the No. 4 sieve where you need to know the retained (i.e. "R4"). AASHTO just % passing.

#4 Dano_PE

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Posted 29 March 2012 - 09:09 PM

Jayman is that % passing TOTAL or CUMULATIVE you need? That is my question. I know how to go back and forth between % passing TOTAL and % passing CUMULATIVE but dont know which set to use for classification charts

#5 Jayman_PE

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Posted 30 March 2012 - 01:10 AM

Use cumulative. Verify this by all the example problems for soil classification - 6 min. geotech solutions, CERM, etc. all use cumulative % passing.


thanks,
Jason

#6 bradlelf

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Posted 30 March 2012 - 02:12 PM

Use cumulative. Verify this by all the example problems for soil classification - 6 min. geotech solutions, CERM, etc. all use cumulative % passing.


thanks,
Jason

+1

#7 Dano_PE

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Posted 31 March 2012 - 03:08 PM

Great. Thanks everyone. Good forum. I was on ppi2pass before and had no replys. You guys are great.

#8 Jayman_PE

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Posted 01 April 2012 - 11:00 PM

I looked at the PPI forum last summer/fall when I started getting set up. It was like a morgue... Came here and it's party time! This is the place to be.

Jason



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