LECTURE NOTES
LECTURE # 1
SOIL AND SOIL ENGINEERING
* The term Soil has various meanings, depending upon the general field in which it is being considered.
*To a Pedologist ... Soil is the substance existing on the earth's surface, which grows and develops plant life.
*To a Geologist ..... Soil is the material in the relative thin surface zone within which roots occur, and all the rest of the crust is grouped under the term ROCK irrespective of its hardness.
*To an Engineer .... Soil is the un-aggregated or un-cemented deposits of mineral and/or organic particles or fragments covering large portion of the earth's crust.
** Soil Mechanics is one of the youngest disciplines of Civil Engineering involving the study of soil, its behavior and application as an engineering material.
*According to Terzaghi (1948): "Soil Mechanics is the application of laws of mechanics and hydraulics to engineering problems dealing with sediments and other unconsolidated accumulations of solid particles produced by the mechanical and chemical disintegration of rocks regardless of whether or not they contain an admixture of organic constituent."
* Geotechnical Engineering ..... Is a broader term for Soil Mechanics.
* Geotechnical Engineering contains:
- Soil Mechanics (Soil Properties and Behavior)
- Soil Dynamics (Dynamic Properties of Soils, Earthquake Engineering, Machine Foundation)
- Foundation Engineering (Deep & Shallow Foundation)
- Pavement Engineering (Flexible & Rigid Pavement)
- Rock Mechanics (Rock Stability and Tunneling)
- Geosynthetics (Soil Improvement)
Soil Formation
* Soil material is the product of rock
* The geological process that produce soil is
WEATHERING (Chemical and Physical).
* Variation in Particle size and shape depends on:
- Weathering Process
- Transportation Process
* Variation in Soil Structure Depends on:
- Soil Minerals
- Deposition Process
* Transportation and Deposition
Four forces are usually cause the transportation and deposition of soils
1- Water ----- Alluvial Soil 1- Fluvial
2- Estuarine
3- Lacustrine
4- Coastal
5- Marine
2- Ice ---------- Glacial Soils 1- Hard Pan
2- Terminal Moraine
3- Esker
4- Kettles
3- Wind -------- Aeolin Soils 1- Sand Dunes
2- Loess
4- Gravity ----- Colluvial Soil 1- Talus
What type of soils are usually produced by the different weathering & transportation process????????????????????????????????????????????????????????????????????????????
- Boulders
- Gravel Cohesionless
- Sand (Physical)
- Silt Cohesive
- Clay (Chemical)
* These soils can be
- Dry
- Saturated - Fully
- Partially
* Also they have different shapes and textures