SOIL MECH T1 Flashcards
In Geotechnical Engineering, this refers to a particle that
consists of three phase solid, liquid (water) and gas (air).
soil
soil refers to a particle that
consists of three phase solid, liquid (water) and gas (air).
geotechnical engineering
refers to a collection of solid particles, of varying sizes, with voids in between which may
contain water.
soil by civil engineers
soil is formed by different particles such as
- gravel
- rock
- sand
- silt
- clay
- loam
- humus
is the sub discipline of civil engineering that involves natural materials found close to the surface of the earth.
geotechnical engineering
defined as a natural aggregate of mineral grains, with or without organic constituents that can be separated by gentle mechanical means such as agitation in water.
soil
is considered to be a natural aggregate of mineral grains
connected by strong and permanent cohesive forces.
rock
are formed by the process of weathering of the parent rock.
soil
types of weathering
- mechanical weathering/mechanical disintegration
- chemical weathering/chemical decomposition
is due to the action of such agents as the expansive forces of
freezing water in fissures, due to sudden changes of temperature or due to the abrasion of rock by moving water or glaciers.
mechanical weathering
can transform hard rock minerals into soft, easily erodible matter.
Chemical weathering (decomposition)
Principle types of decomposition
- Hydration
- oxidation
- carbonation
- desilication
- leaching
Three basic types of soils
- sand
- silt
- clay
classification of soil according to grain size acc. to USCS
- gravel: 4.75 to 76.2 mm
- sand: less than 4.75 to 0.075 mm
- silt: 0.075 to 0.002 mm
- clay: finer than 0.002 mm
are mixtures in which a significant part of the solids is derived from the growth and decay of plant life and/or from the accumulation of skeletons or shells of small organisms.
organic soils
is a good example of an organic soil, consisting largely of decaying wood and other plant remains.
peat
are formed as a result of the breaking down of rocks into smaller fragments.
inorganic soils
purely mechanical process
physical weathering (disintegration)
chemical alteration of the parent material
chemical decomposition
is the material resulting from the in situ weathering of the parent rock.
residual soil
Residual soils are distributed throughout many regions of the world, such as
Africa, South Asia, Australia, Southeastern North America, Central and South America, and considerable regions of Europe.
are soils that are found at locations far removed from their place of formation.
transported soils
the transporting agencies of soils
glaciers, wind, water
transported by running water and deposited along streams and so-called alluvial plains
Alluvial Soils
transported and deposited by wind. Examples: Sand dunes, air transported volcanic deposits, Loess.
Aeolian Soils
formed by movement of soils from its original place by gravity, such as during landslides.
Colluvial Soils
formed by deposition in quiet lakes.
Lacustrine Soils
formed by transportation and deposition of glaciers.
Glacial Soils
formed by deposition in the seas.
Marine Soils
is generally understood to refer to a material composed of a mass of small mineral particles which, in association with certain quantities of water, exhibits the property of plasticity.
clay
extremely small crystalline particles of one or more members of a small group of minerals
clay minerals
Clay is divided into three general groups based on
Crystalline arrangement
