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Soil Mechanics > Lesson 2: Physical Properties > Flashcards

Lesson 2: Physical Properties Flashcards

1
Q

It is composed of solids, liquids, and gases

A

soil

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2
Q

it may be minerals, organic matter, or both.

A

solid phase

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3
Q

the spaces between the solids (solid particles)

A

voids

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4
Q

_____________ is the predominant liquid and ______________ is the predominant gas.

A

Water, Gas

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5
Q

The soil water is called the ___________ and plays a very important role in the behavior of soils under load.

A

porewater

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6
Q

If all voids are filled with water, it is ___________

A

saturated

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7
Q

If no water in the void space, it is _____________

A

dry

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8
Q

If the void is partially filled with water , it is ___________

A

moist

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9
Q

The physical parameters of soils are influenced by the
relative proportions of each of these phases. (True or False?)

A

True

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10
Q

The ratio of the amount of water (Ww) in the soil
(Ws) and expressed as a percentage.

A

Water Content, w

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11
Q

The ratio of the volume of void space (Vv) to the volume of solids (Vs). It is usually expressed as a
decimal quantity.

A

void ratio, e

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12
Q

The volume of soil per unit volume of solids. This
equation is useful in relating volumes.

A

Specific Volume, V’

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13
Q

The ratio of the volume of voids (Vv) to the total
volume (V).

A

porosity, n

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14
Q

The maximum and minimum porosities would be ______ and _______, respectively

A

48% and 26%

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15
Q

The maximum and minimum porosities stated is equivalent to maximum and minimum void ratios of _______ and _______, respectively.

A

0.91 and 0.35

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16
Q

The void ratios of real coarse-grained soils vary between _________ and _______

A

1 and 0.3

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17
Q

Clay soils often have void ratios greater than 1. (True or False?)

A

True

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18
Q

The ratio of the volume of water to the volume of
voids, often expressed a percentage.

A

Degree of Saturation, S

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19
Q

If S=1 or 100%, the soil is ____________.

If S=0, the soil is _____________.

A
  1. saturated
  2. dry
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20
Q

The weight of soil per unit volume (bulk unit
weight/ moist unit weight)

A

Unit weight, y

21
Q

Special cases in unit weight

A
  1. Saturated unit weight
  2. Dry unit weight
  3. effective or buoyant unit weight
22
Q

Considering the limits of unit weights for soils, we will use the ratio of the soil’s unit weight to that of water. This ratio is a dimensionless quantity label as _____.

A

Rd (unit eight ratio or density ratio)

23
Q

This is an index that indicates the degree of packing between the loosest and densest possible state of
coarse-grained soils as determined by experiments.

A

Relative Density, Dr

24
Q

This is similar (not identical) to relative density (Dr)

A

Density Index

25
Q

This is a ratio of the volume of excavated material
to the volume of in-situ material (sometimes called borrow
pit material or bank material)

A

Swell factor (SF)

26
Q

The physical and mechanical behavior of fine- grained soils is linked to four distinct states:

A

solid, semisolid, plastic, and liquid, in order of increasing water content.

27
Q

Point A – original liquid state. As the soil dries, its water
content reduces and so does its volume.

Point B – the soil becomes so stiff that it can no longer
flow as a liquid.

The boundary water content at point B is called the liquid
limit; it is denoted by _____

A

Liquid Limit (LL)

28
Q

Point C – the water content at which the soil changes from
a plastic to a semi-solid is known as the ___________

A

Plastic Limit (PL)

29
Q

If drying is continued beyond the range of water
content for plastic behavior, the soil becomes a ______________.

A

semisolid

30
Q

The range of water content over which the soil deforms
plastically is known as the __________

A

Plasticity Index, PI = LL-PL

31
Q

As the soil continues to dry, it comes to a final state called
the _________. At this state, no further volume change
occurs because nearly all the water in the soil has been
removed.

A

soild state

32
Q

Point D – the water content at which the soil changes from a semisolid to a solid is known as _________

A

Shrinkage Limit, SL

33
Q

The range of water content from the plastic limit to the
shrinkage limit for which the soil behaves as a semisolid is
called the _______________

A

Shrinkage index, SI = PL-SL

34
Q

He developed a method to describe the consistency of fine-grained soils with varying ω.

A

Albert Atterberg, 1911

35
Q

Index parameters are:

A

a) Plasticity Index (PI= LL-PL)
b) Liquidity Index (LI = ω-PL / LL-PL)
c) Shrinkage Index (SI= PL-SL)

36
Q

It is the moisture content after 25 blows
or moisture content at which a soil changes from the
liquid state to the plastic state.

A

Liquid Limit (LL)

37
Q

The liquid limit is determined from an apparatus
that consists of a semispherical brass cup that is
repeatedly dropped onto a hard rubber base from a height
of 10mm by a cam operated mechanism. The apparatus is called _________

A

Casagrande Cup

38
Q

It is a moisture content in percent at which the soil
crumbles, when rolled into threads of 3.2mm
(1/8”) in diameter.

A

Plastic Limit (PL)

39
Q

-it is the relative consistency of a cohesive soil in the
natural state.

-ratio of the difference in water content between
the natural or in-situ water content of a soil and
its plastic limit to its plasticity index.

A

Liquid Index, LI

40
Q

_______________ or simply consistency is analogous to
viscosity in liquids and indicates internal resistance to
forces that tend to deform the soil.

A

soil consistency

41
Q

The internal resistance of soil may come from inter-particle
forces (cohesion or adhesion), cementation, inter-particle
friction, and soil suction. (True or False)

A

True

42
Q

Consistency changes with water content (True or False)

A

True

43
Q

A measure of consistency is provided by the __________

A

Consistency Index , CI

44
Q

For soils with a particular mineralogy, the plasticity index
is linearly related to the amount of the clay fraction. This is called ______________

A

Activity, A= PI/ Clay fraction (%)

45
Q

_____________ is one of the factors used in identifying expansive or swelling soils.

A

Activity, A

46
Q

Classification of Clay based on Activity (A):

A

A< 0.70 = Inactive
0.70 < A < 1.20 = Normal
A>1.20 = Active

47
Q

It is the Moisture content (in percent) which the volume
of the soil mass ceases to change.

A

Shrinkage Limit, SL

48
Q

Three limits are defined based on the water content
that causes a change of state. These are:

A

a. liquid limit (LL) - the water content that caused the soil to
change from a liquid to a plastic state;
b. plastic limit (PL)- the water content that caused the soil to change from a plastic to a semisolid; and
c. shrinkage limit (SL) - the water content that caused to change from a semisolid to solid.

49
Q

The soil strength is lowest at the liquid state and highest at the solid state. (True or False?)

A

True

Soil Mechanics (2 decks)

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