Download Definition of an engineering soil Soil is an uncemented (or weakly

Definition of an engineering soil
Soil is an uncemented (or weakly cemented)
accumulation of mineral particles formed by the
weathering of rocks, the void space between the
particles, containing water and/or air.
1
Figure 1.1. The rock cycle
2
Scale
Figure 1.6. Single grain structure
3
Figure 1.1. Clay (kaolin).
4
1
Silica sheet
Gibbsite sheet
Silica-gibbsite sheet
5
Figure 1.1. The rock cycle
kaolinite
illite
6
montmorillonite
Water molecule
Figure 1.8. Clay minerals.
7
8
2
Specific surface: Surface area per unit mass
Sand
Small Specific surface
Coarse sand
0.002m2/g
1mm diameter
Fine sand
0.02m2/g
0.1mm diameter
Silt
0.2m2/g
0.01mm diameter
Dispersed
Flocculated
Natural soil
Figure 1.9. Clay structure
Sieve analysis
Clay
Large Specific surface
Kaolinite
10 - 20m2/g
Illite
65 - 100m2/g
0.1m thick
Montmorillonite
up to 800m2/g
0.01m thick
9
11
1m thick
10
Hydrometer
12
3
Non-plastic
Plastic
13
Plastic limit test
Liquid limit test
Casagrande apparatus
14
Fall cone apparatus
15
16
4
Figure 1.12. Plasticity chart
17
Figure 1.1. The rock cycle
18
Description of soil
Jennings, Brink and Williams (1973)
M - Moisture
C - Colour
C - Consistency
S - Structure
S - Soil type
O - Origin
19
20
5
Description of soil
Description of soil
Structure
Cemented / bonded
Fissured (closed joints)
Jointed
Bedding planes
Intact (no joints of fissures)
Slickensided
Moisture
Dry
Slightly moist
Moist
Very moist
Wet
Soil type
Clay / silt / sand / gravel
Consistency
Coarse material
Fine material
Very loose
Very soft
Loose
Soft
Medium dense
Firm
Dense
Stiff
Very dense
Very stiff
Origin
Geological origin
21
Figure 1.15. Phase diagrams
22
23
6