This document presents a presentation on identifying and classifying soils according to the Unified Soil Classification System. It begins by outlining the objectives and test standards. It then describes the process of first identifying soils as coarse-grained or fine-grained based on particle size and visibility. For coarse-grained soils, it details how to further classify them as sandy or gravelly soils. For fine-grained soils, it explains using dispersion, dilatancy, plasticity, dry strength, and organic tests to classify them as inorganic or organic silts/clays. Primary group symbols are assigned based on liquid limit and field/laboratory test behaviors.

1. WELCOME TO OUR PRESENTATION
Submitted To
Prof. Dr. Md. Abu Taiyab
Dept. Of CE.
Mr. Md . Ariful Islam
Lecturer, Dept. of CE.
Prepared By
MD. Parvej
ID: 131046
Syed Shahjalal
ID: 131021
DEPARTMENT OF CIVIL ENGINEERING.
DHAKA UNIVERSITY OF ENGINEERING & TECHNOLOGY ,GAZIPUR.

2. IDENTIFICATION AND
CLASSIFICATION OF SOIL
COURSE NO. CE -3302
GEOTECHNINICAL ENGINEERING -I SESSIONAL

3. Objectives
 The test is Standardized in ASTM D 2487 as “ Unified Soil Classification
System”.
Test Standard
The classification of soils is based on a combination of visual observation and
laboratory tests.
This system needs to be comprehensive, while still being reasonable, systematic
and concise.

4. STEP-1 (IDENTIFYING AS COARSE GRAINED
SOIL OR FINE GRAINED SOIL)
Soil Sample
Fine
grained
soil
Coarse
grained
soil
• Naked eye visibility>50%
• Size :-particle size
within76mm to 0.075mm
• Naked eye visibility<50%
• Size :- particle size less
than 0.075mm

5. Naming Convention
Primary
Letter
Soil
compone
nt
Size & Description
G Gravel
Coarse:75mm-19mm
Fine:19mm-4.75mm
S Sand
Coarse:4.75mm-2.0mm,
Medium: 2.0mm-425μm,
Fine: 425μm -75μm
M Silt
Particles smaller than 75μm,
identified by plasticity
C Clay
Particles smaller than 75μm,
identified by plasticity
O
Organic
Metter
Organic matter in various size &
stages of decomposition
Pt Peat Highly organic soils
Secondary Letter Description
W Well graded
P Poorly graded
M Non- plastic fines i.e. silt
C Plastics fines i.e. clay
L Low plasticity, WLL< 50%
H High plasticity, WLL>50%

6. STEP-2 (CLASSIFYING COARSE GRAINED SOIL)
Coarse Grained
Soil
Sandy soil
Gravelly soil
GPGW
Dust Gravel
Fines>12%
Clean Gravel
Fines<5%
Dust sand
Fines>12%
Clean sand
Fines<5%
GM SPSW SCSM
GC

7. STEP-3 (CLASSIFYING FINE GRAINED SOIL)
Fine Grained
Soil
Organic
Soil
Inorganic
soil
• Dispersion Test
• Shaking or Dilatency Test
• Plasticity Test
• Dry Strength Test
• Presence of organic matter
• Dark Gray to Black Color
• Oder of Decaying vegetation
• More compressible

8. Primary
division
Group
symbol
Description
Field criteria
Dilatancy Dry strength Plasticity
Silts & Clays
(Liquid limit
less than 50%)
ML
Inorganic silts of low
plasticity
Quick to slow None to slight None to slight
CL
Inorganic clays of low
plasticity
None to very
slow
Medium to
high
Medium to slight
OL
Organic silts of low
plasticity
Slow Slight to
Medium
Slight
Silts & Clays
(Liquid limit
more than
50%)
MH
Inorganic silts of high
plasticity
Slow to none Slight to
Medium
Slight to Medium
CH
Inorganic clays of high
plasticity
None High to very
high
High
OH
Organic clay of high
plasticity
None to very
slow
Medium to high Slight to Medium
Highly organic
Soils
Pt
Peat and other highly organic soils Organic color, odor, spongy feels,
frequently fibrous.

9. Test of inorganic soil
Test name Performance Observation comments
• Dispersion Test The soil was allowed
to settled in water
Most of soil grain was
settled within 30sec
Sandy Silt
• Shaking or
Dilatency Test
A moist soil mass was
shaken on palm by
tipping
Slow Clayey soil
• Plasticity Test Manipulation of 3mm
thread
3mm thread was
formed
Silty Clay
• Dry Strength Test A dry 3mm rolled
fragment was
enforced.
A great effort was
needed
Clay soil

10. &
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