Environmental Engineering Reference
In-Depth Information
TABLE 5.34
ASEE System of Definition for Visual Identification of Soils
a
Definition of Soil Components and Fractions
Granular Material
Symbol
Fraction
Sieve Size and Definition
Boulders
Bldr
9 in.
Cobbles
Cbl
3 to 9 in.
Gravel
G
Coarse (c)
1 to 3 in.
Medium (m)
1 to 1 in.
Fine (f)
No. 10 to 3/8 in.
Sand
S
Coarse (c)
No. 30 to no. 10
Medium (m)
No. 60 to no. 30
Fine (f)
No. 200 to no. 60
Silt
S
Passing no. (0.074 mm). (material
nonplastic and exhibits little
or no strength when air-dried)
Organic silt
OS
Material passing no. 200. exhibiting:
(1) plastic properties within a
certain range of moisture content
and (2) fine granular and organic
characteristics
Clay
See below
Material passing no. 200 which can
be made to exhibit plasticity and
clay qualities within a certain
of moisture content and which
range exhibits considerable
strength when air-dried
Clay material
Symbol
Plasticity
Plasticity Index
Clayey SILT
CyS
Slight (SL)
1-5
SILT and CLAY
S&C
Low (L)
5-10
CLAY and SILT
C&S
Medium (M)
10-20
Silty CLAY
SyC
High (H)
20-40
CLAY
C
Very high (VH)
40
Definition of Component Proportions
Component
Written
Portions
Symbol
Percentage Range by Weight
Principal
CAPITALS
50 or more
Minor
Lower case
And
a
35-50
some
s
20-35
little
L
10-20
trace
t
1-10
a
sign, upper limit: no sign, middle range. (After Burmister, D.M., American
Society for Testing and Materials, Philadelphia, PA, 1948. Copyright ASTM. Reprinted with permission.)
sign, signifies lower limit:
Gradation
MIT system
: Materials are described from visual examination in terms of the major com-
ponent with minor components and sizes as modifiers, such as ”silty fine to medium
sand,” ”clayey silt,” or ”clayey fine sand.”
Unified Classification System Nomenclature
Soil particles: G — gravel, S — sand, M — silt, C — clay, O — organic
●
Granular soil gradations: W — well graded, P — poorly graded
●
Cohesive soils: L — low plasticity, H — high plasticity
●
Major divisions:
Coarse-grained soils: more than one half retained on no. 200 sieve
●
