mohanad.alfach

1
Soil Classification Basics

• Dr. Mohanad Alfach
• Ph.D. in Earthquake Geotechnical Engineering

2
Contents

• Soil Classification Systems
• Criteria's of (USCS) soil classification
• Soil Grain Sizes
• Hydrometer analysis
• Soil Plasticity Atterberg Limits
• AASHTO soil classification
• Classification Steps according to AASHTO
• Group Index (GI) Formula

3
Soil classification usually based on grain size
and soil consistency. Several classification
systems exist 1- Unified Soil Classification
System (USCS) according to (ASTM D2487-11) 2-
American Association of State Highway and
Transportation Officials AASHTO according to
(ASTM D3282-09) 3-U.S. Department of Agriculture
(USDA). 4- Burmister Soil Identification
System. 5-Massachusetts Institute of Technology
(MIT)
4
Steps of USCS Process

• Coarse-Grained
• Gravel
• Sand

Sieve Analysis
Sieve Analysis
Grain Size Distribution, Cc, Cu
Grain Size Distribution, Cc, Cu
Percent Clay ( lt 2mm)
Percent Clay ( lt 2mm)
Plasticity Chart
Plasticity Chart

• Fine-Grained
• Silt
• Clay

Hydrometer Analysis
Hydrometer Analysis
PI
PI
LL
Liquid Limit
Plastic Limit
Plastic Limit
LL
Liquid Limit
5
(No Transcript)
6
(No Transcript)
7
Mechanical Sieve Analysis (ASTM D422 , D1140 and
AASHTO T88)
8
(No Transcript)
9
(No Transcript)
10
(No Transcript)
11
(No Transcript)
12
(No Transcript)
13
In general. PI Degree of Plasticity 0 Non
plastic 1-5 Slightly plastic 5-10 Low
plasticity 10-20 Medium plasticity 20-40 High
plasticity 40 Very high plasticity (from
Burmister, 1949)
14
(No Transcript)
15
(No Transcript)
16
200
40
10
17
(No Transcript)
18
(No Transcript)
19
(No Transcript)
20
(No Transcript)
21
(No Transcript)
22
(No Transcript)
23
(No Transcript)
24
(No Transcript)
25
(No Transcript)
26
(No Transcript)
27
(No Transcript)
28
(No Transcript)
29
Thanks for your time and attention!
Questions?
30
(No Transcript)