Environmental Engineering Reference
In-Depth Information
TABLE 5.33
Unified Soil Classification System (ASTM D-2487)
Group
Symbols
Typical Names
Laboratory Cla ssfcation C riteri a
Major Division
D
60
D
10
(D
30
)
2
D
10
x D
60
Well-graded gravels, gravel-
sand mixtrues, little or
no fines
greater than 4:C
c
=
G
W
Cu
=
between 1 and 3
Poorly graded gravels, gravel-
sand mixtures, little or
no fines
Not meeting all gradation
requirement for GW
GP
Atterberg
limits below
" A " line or
PI less than
4
Silty gravels, gravel-
sand clay mixtures
GM
d
Above " A " line
with Pl between
4 and 7 are border
line cases requiring
use of dual
symbols
u
Atterberg
limits below
" A " line or
PI greater
than 7
GC
Clay gravels, gravel
sands, little or no fines
D
60
D
10
(D
30
)
2
D
10
x D
60
Well-graded sands,
gravelly sands, little or
no fines
Poorly graded sands,
gravelly sands, little or
no fines
SW
greater than 4:C
c
=
Cu
=
between 1 and 3
SP
Not meeting all gradation
requirements for SW
Atterberg
limits above
" A " line or
PI less than 4
d
Silty sands, sand-
silt mixtures
SM
a
u
Limits plotting
in hatched
zone with PI
between 4 and
7 are
borderline
caes requiring
use of dual
symbols
Atterberg
limits above
" A " line with
PI greater
than 7
Clayey sands,
sand-clay
mixtures
S C
ML
Inorganic silts and
very fine, rock
flour, silty or clayey
fine sands, or clayey
silts with slight
plasticity
Plasticity chart
60
Inorganic clays of
low to mediem
plasiticity, gravelly
clays, sandy clays,
silty clays, lean
clays
C
L
50
CH
40
OL
Organic silts and
organic silty clays
of low plasticity
30
OH and MH
MH
20
Inorganic silts,
micaceous or
diatomaceous fine
sandy or silty soils,
elasticsilts
CL
10
CL-ML
Ml and
OL
0
C
H
Inorganic clays of
high plasticity, fat
clays
0
10
20
30
40
50
60
70
80
90
100
Liquid limit
Pt
Peat and other highly
organic soils
