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53 Cards in this Set
- Front
- Back
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what are the two shear strength parameters
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cohesion
frictional resistance |
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the ability to resist shear stresses
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shear strength
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sloping hillsides-landslides and footings are ____________
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shear stresses
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adhesion between particles
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cohesion
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sliding and interlocking between particles is
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frictional resistance
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degree of compaction between loosest state and densest state
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compactness
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low void ratio
highest shear strength greatest resistance to compression |
DENSEST state
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high void ratio
low shear strength low resistance to compression |
LOOSEST state
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Dr
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relative density
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Dr<15%
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very loose
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Dr 15-35%
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loose
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Dr 35-65%
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medium dense
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Dr 65-85%
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dense
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Dr >85%
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very dense
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few points of contact
poor interlocking high permeability |
poorly graded
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good interlock
low permeability |
well graded
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only limited sizes
good interlock low permeability |
gap graded
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1. compaction effort
2. moisture content 3. soil type and gradation |
field compaction efforts
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3 types of grain size distribution
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poorly graded, well graded, gap graded
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2 shapes of grains
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angular
rounded |
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the type and amount of clay present helps to determine
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the soil type
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is uniformly graded sand good for compaction
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no
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are clays of high plasticity good for compaction
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no
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are organic silts and clays good for compaction
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no
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are natural soils in the loose state or the dense state
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in between the states
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what lubricates soil particles
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water
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what creates clay particle bonding
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water
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is it easy to achieve density if soil is too wet or too dry
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no, nearly impossible
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within what range must the moisture be to achieve density
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optimum range
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moisture control for clay:
top 3' - max w%= |
optimum
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moisture control for clay:
below 3' - max w%= |
optimum + 3%
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8" layer compacted to 6" depth is the
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lift thickness
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definition:
an entire void space filled with water |
saturation
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definition:
water movement within soil |
permeability
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definition:
water seeps up into the soils above |
capillary flow
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what has the greatest capillarity
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silts and very fine sand
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definition:
vertical expansion of soil |
frost heave
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soil compressed-volume decreased
related to void ratio results from loading extrusion of water or voids from soil varies if cohesive soil or not |
compressibility
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volume of air and water combined
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voids
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voids are completely filled with water
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saturated
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W
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weight
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V
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volume
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w
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water
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t
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total weight
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a
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air
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s
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solids (dry weight)
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v
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voids
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e
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void ratio
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S
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saturation
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Gs
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specific gravity
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n
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perocity
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a measure of how porous it is
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perocity
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wavelength sign
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unit weight
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