compression index of soil?
compression index of soil?
(OP)
We have an engineer in the office that takes a certain amount of joy in testing me. He returned some consolidation test results to me with a note asking for the Cc (compression index) of each soil sample. The what? He claimed it could be solved for with the info from the tests. I searched ASTM D-2435, Standard Test Method for One-Dimensional Consolidation Properties of Soils, and found nothing. Is this guy pulling my chain or is there really a formula for this? And if so, where?





RE: compression index of soil?
p.s. Now, yank his chain and ask him about alternative methods of determining the preconsolidation pressure other than Casagrande's method. (For your information, this was discussed in detail in a paper I found on the internet, but I saw many years ago in Geotechnique - plot loge-logp and it is the intersection of the two before and after curves on the plot.
RE: compression index of soil?
OK, this what I have:
void ratio at start of test is .93 eo
void ratio at end of test is .72 ef
P1 = 1.0 tsf and e1 = .95
P2 = 10 tsf and e2 = .67
the Cc = .210
RE: compression index of soil?
RE: compression index of soil?
RE: compression index of soil?
If you could report the test results to us in a tabular form (just the e and applied pressure values should suffice) then we could help you interpret them.
You are correct. Both points used for estimating Cc from 1-d consol test results need to be on the NC or virgin compression curve.
ASTM D2435 shows examples of how to obtain the Cc and Cr/Cs slopes, depending on the method used to perform the test.
Jeff
Jeffrey T. Donville, PE
TTL Associates, Inc.
www.ttlassoc.com
RE: compression index of soil?
RE: compression index of soil?