Soil Flashcards
Soil vs. Rock similarities
both are natural aggregate of mineral grains
Soil vs Rock differences
- soil aggregates can be separated by mechanical means (agitation in water)
- Rock aggregate minerals are connected by stronger forces
Soils are products of….?
rock weathering
gravel =
sand =
silt =
clay =
- gravel = small rocks
with a mix of minerals. - sand = small grains of a SINGLE mineral
- silt = same but grains not visible to naked eye
- clay = tiny plate-like minerals
why is soil called a 3-phase material?
solid - soil grains
liquid - usually water
gas - usually air
soil is a frictional material. Does it have tensile strength?
NO
does soil exhibit linear plastic behaviour?
NO, non-linear
Soil is anisotropic and heterogenous, what does that mean?
huge range of properties. Every soil is different, different in each location and huge variety
geotechnical challenges of soil
- settlement
- strength (bearing capacity and slope stability
- seepage
- liquefaction
residual vs transported soil
residual is a product of rock weathering and remains in place, transported is taken to other locations
where would you find clay minerals with good drainage and soils with good engineering properties?
hilly and mountainous areas.
flat low-lying areas produce what type of soils?
poor drainage with little or no vertical seepage. Bad engineering properties
Aeolian, fluvial and glacial soils
aeolian transported by wind, fluvial rivers/streams, glacial glaciers
volcanic soils
- layers represent seperate volcanic events
- high water content
- ash soils tend to drain quickly (no puddles)
- often sensitive
sorting process of transported soils, leads to more __________ deposits (especially fluvial and aeolian)
homogeneous deposits
residual soils formation
formed by growth and decay of plants (peat, mosses) or accumulation of fragments of inorganic skeletons or shells
Auckland clays are a common example of?
residual soil
traditional soil mechanics is based on the properties of which soil type?
transported
would angular sand grains or round sand grains be stronger?
angular, because they can interlock
what dominates the behaviour of clay ?
water interaction