estimation of soil compaction parameters based on the atterberg limits
Soils Classification Testing overview of test procedures to classify ... Atterberg Limits –...
Transcript of Soils Classification Testing overview of test procedures to classify ... Atterberg Limits –...
Soils Classification Testing
An overview of test procedures to classify soils according to the Uniform Soil
Classification System (ASTM D 4287)
John S. Landwermeyer, P.E.
Austin, Texas
ARIAS & ASSOCIATES, INC.Geotechnical · Environmental · Materials Testing
Sieve Analysis (ASTM D 421)Representative SampleDry Sample to get total dry weight (Night 1)Wash sample over the #200 SieveDry Sample (Night 2)Dry shake through sievesWeigh contents of each sieve% Retained = Wt Retained ÷Total Wt
Sieve Analysis – Possible ErrorsUn-representative Sample
SegregationInsufficient wash of sample over the #200 Sieve: use brush!Over-loading of sieve nestTare weights, human errors
Atterberg Limits – Soil PrepRepresentative SampleSoak for up to 12 hours (“slaking time”) (Night 1)Remove aggregate on #10 sieve
Atterberg Limits – Soil PrepRepresentative SampleSoak for up to 12 hours (“slaking time”) (Night 1)Remove aggregate on #10 sieveMechanical mixing
Atterberg Limits – Soil PrepRepresentative SampleSoak for up to 12 hours (“slaking time”) (Night 1)Remove aggregate on #10 sieveMechanical mixingPour thru #40 sieve, into lined absorbent bowlAllow soil to dry to below the Liquid Limit (Night 2)
Atterberg Limits – Liquid LimitAdjust moisture to the Liquid LimitLL is reached when ½” of the grove closes after 25 blows
Atterberg Limits – Plastic LimitAdjust moisture to the Plastic LimitPL is reached when soil begins to break when rolled into 1/8” threads
Atterberg Limits – Plasticity Index PI = LL – PL
“Fat Clay” = LL > 50 (ASTM D 2487)“Lean Clay” = LL < 50 (ASTM D 2487)“Expansive” = PI > 20 Non-cohesive = non-plastic = sand, silt or gravel
Atterberg Limits – Possible ErrorsUn-representative sample or sub-sampleDry preparation (ASTM D 4318) pulverization of soils containing rock decreases PI