Soil Classification

[Dano_PE]

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!

 

[evrick1952]

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

 

[Jayman_PE]

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.

 

[Dano_PE]

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

 

[Jayman_PE]

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

thanks,

Jason

 

[bradlelf]

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

 

[Dano_PE]

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

 

[Jayman_PE]

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