CMP 305 Exam Study Guide.
All shapes of soils - answer✔✔angular
subangular
rounded
why do angular particles have better engineering properties - answer✔✔less voids
Clay particle properties - answer✔✔very fine and layered flat
attracts water the most
charges for clay - answer✔✔mineral surface negative charge
edges have positive charge
sieves are used for what kind of soil - answer✔✔coarse grained
what do classification tests determine - answer✔✔direct physical sizing of material
and sedimentaion
sedimentation - answer✔✔process of settling
well graded - answer✔✔wide range of sizes
poorly graded - answer✔✔small range of sizes
what kind of soil is most suseptible to soil liquefaction - answer✔✔poorly graded
soil liquefaction - answer✔✔strength and stiffness reduced by high loads or vibrations
fine grained based on sieve - answer✔✔more than 50% passes through 200# seive
Dry strength test - answer✔✔Mold sample into ball and let dry, break ball with thumb and finger
dry strength test if ball doesnt break - answer✔✔highly plastic
dry strength test if ball breaks - answer✔✔not very plastic
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plasticity index depends on what - answer✔✔amount of clay present
plastic index indication - answer✔✔fitness of the soil and its capacity to change shape without
altering volume
Clay properties vary in proportion to - answer✔✔water content
high water content in clay has ___________ Properties - answer✔✔liquid
Low water content and volume decrease in clay shows that it is - answer✔✔plastic
Atterberg limits evaluate - answer✔✔plasticity
atterberg limits used when - answer✔✔for dams, embankments,landfills,highways
atterberg limits determine - answer✔✔if building can be supported
Liquid Limit - answer✔✔soil water content expressed in % of dry unit weight
Liquid limit point - answer✔✔which soil will start to flow using the shake test ( more water
content)
Plastic limit - answer✔✔moisture content % at soil begins to crumble ( less water content)
Plastic index - answer✔✔numericle difference between liquid and plastic limits
plastic index represent - answer✔✔range in moisture content
In field devices - answer✔✔soil density devices
pocket penetrometer
turvane
pocket penetrometer measures - answer✔✔tons per square foot
in place density or in place unit weight refers to what - answer✔✔volumetric weight of soil in
undisturbed condition or compacted fill in pounds per square foot
IPD or IPUW only used for - answer✔✔coarse grained soils due to there being such a difference
in bank and compacted density and volume
The greater the density or unit weight the better the... - answer✔✔shear strength and less
tendancy for compression
borrow pit soils - answer✔✔an area to remove earth soils which will be used for fill
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use unut weight or density tests to estimate - answer✔✔volume of shrinkage or swell that will
occur as the soil is transported
collapsible soils have - answer✔✔volume reductions when in contact with water
collapsible gravel has what change - answer✔✔volume
saturated sand is - answer✔✔unstable
montmorillte minerals have high - answer✔✔volume changes
easy to absorb water where - answer✔✔between layers
expansive force can lift - answer✔✔pavements and structures
expansive force puts lateral forces and - answer✔✔pressure on walls
volume decrease occurs when there is - answer✔✔a decrease in water content
significant ground settlement creates - answer✔✔shifting
expansive swelling clays monitor - answer✔✔soil moisture and control percentage around or
beneath the structure
Option to control soil moisture and water content - answer✔✔chemical stabilization
controlling soil moisture for small areas - answer✔✔remove and replace
controlling soil moisture for large areas - answer✔✔remove water
chemical stabilization with lime slurry mix
piles stabilize soil wall
Bentonite clay - answer✔✔type of clay that is highly effective in preventing water infiltration in
buildings.
Bentonite clay commonly used for - answer✔✔foundation waterproofing , landscaping, sealing
and cement additive
soil test identify - answer✔✔problems that are present
options for soil problems that are present - answer✔✔plan around problem
Function of soil based on - answer✔✔soil type
soil moisture