SOIL MECHANICS
AND FOUNDATION ENGINEERING-I (CE-210)
•
BOOKS
1.
SOIL MECHANICS by T WILLIAM LAMBE & ROBERT V. WHITMAN, Wiley ASTERN
2.
FOUNDATION ANALYSIS & DESIGN by JOSEPH E. BOWLES, Mc Graw Hills
3.
GEOTECHNICAL ENGINEERING by SHASHI K GULHATI & MANOJ DATTA, TATA Mc
Graw Hill
4.
SOIL MECHANICS AND FOUNDATION ENGINEERING by B C PUNMIA, A K JAIN & A
K JAIN, Laxmi Publications Pvt. Ltd.
SOIL
An assemblage of discrete solid particles of organic and
inorganic composition with air with and/ or water
occupying the void space amongst the particles.
Soil thus can have THREE PHASES present: Solid, water
and air.
If no air present: Saturated Soil
If no water present: Dry Soil
FORMATION OF SOIL
Soils are formed by numerous processes of weathering, both
physical and chemical.
Soils are of two categories :
• Residual Soils: Found at the location where they have been
formed.
• Transported Soils: Formed at one location and are transported
at new location where they are deposited.
TRANSPORTED SOILS
The characteristics of transported soil are determined by three factor:
•
Condition at formation
•
Transporting Agents
•
Environment in which the soil is finally deposited
Formation (Condition)
Parent Rock
Weathering Process
Transportation (Agencies)
Water
Wind
Ice
Gravity
Deposition (Environment)
Fresh water body
Salt water body
River Banks
Land Region
TRANSPORTED SOILS
1. Soils that are carried and deposited by rivers are called alluvial
deposits.
2. Soils that are deposited by flowing water or surface runoff while
entering a lake are called lacustrine deposits. Alternate layers
are formed in different seasons depending on flow rate.
3. If the deposits are made by rivers in sea water, they are
called marine deposits. Marine deposits contain both particulate
material brought from the shore as well as organic remnants of
marine life forms.
4. Melting of a glacier causes the deposition of all the materials
scoured by it leading to formation of glacial deposits.
5. Soil particles carried by wind and subsequently deposited are
known as aeolian deposits
CLASSIFICATION OF SOIL BASED ON GRAIN SIZE
76.2
Gravel-size
Cobble-size
Fine
Coarse
19.1
Coarse
4.76
Fine
2
Sand-size
Medium
0.42
0.074
Silt-size
0.002
Clay-size
Diameter, D (mm)
Unified Classification System (Adopted by ASTM & ASCE)
CLASSIFICATION OF SOIL BASED ON GRAIN SIZE
Diameter, D (mm)
BIS IS 1498-1970 (Reaffirmed 1987)
80
Gravel-size
Cobble-size
Fine
Coarse
20
Coarse
4.75
Fine
2
Sand-size
Medium
0.425
Silt-size
0.075
0.002
Clay-size
CLASSIFICATION OF SOIL BASED ON GRAIN SIZE
Diameter, D (mm)
US Bureau of Soils
Gravel-size
Fine
2
Coarse
0.5
Fine
0.25
Sand-size
Medium
0.1
Silt-size
0.05
0.005
Clay-size
CLASSIFICATION OF SOIL BASED ON GRAIN SIZE
Diameter, D (mm)
MIT System
Coarse
2
Fine
0.6
Sand-size
Medium
0.2
Coarse
0.06
Fine
0.02
Silt-size
Medium
0.006
0.002
Clay-size
Gravel-size