Lesson 2: Physical Properties Flashcards
It is composed of solids, liquids, and gases
soil
it may be minerals, organic matter, or both.
solid phase
the spaces between the solids (solid particles)
voids
_____________ is the predominant liquid and ______________ is the predominant gas.
Water, Gas
The soil water is called the ___________ and plays a very important role in the behavior of soils under load.
porewater
If all voids are filled with water, it is ___________
saturated
If no water in the void space, it is _____________
dry
If the void is partially filled with water , it is ___________
moist
The physical parameters of soils are influenced by the
relative proportions of each of these phases. (True or False?)
True
The ratio of the amount of water (Ww) in the soil
(Ws) and expressed as a percentage.
Water Content, w
The ratio of the volume of void space (Vv) to the volume of solids (Vs). It is usually expressed as a
decimal quantity.
void ratio, e
The volume of soil per unit volume of solids. This
equation is useful in relating volumes.
Specific Volume, V’
The ratio of the volume of voids (Vv) to the total
volume (V).
porosity, n
The maximum and minimum porosities would be ______ and _______, respectively
48% and 26%
The maximum and minimum porosities stated is equivalent to maximum and minimum void ratios of _______ and _______, respectively.
0.91 and 0.35
The void ratios of real coarse-grained soils vary between _________ and _______
1 and 0.3
Clay soils often have void ratios greater than 1. (True or False?)
True
The ratio of the volume of water to the volume of
voids, often expressed a percentage.
Degree of Saturation, S
If S=1 or 100%, the soil is ____________.
If S=0, the soil is _____________.
- saturated
- dry
The weight of soil per unit volume (bulk unit
weight/ moist unit weight)
Unit weight, y
Special cases in unit weight
- Saturated unit weight
- Dry unit weight
- effective or buoyant unit weight
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 _____.
Rd (unit eight ratio or density ratio)
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.
Relative Density, Dr
This is similar (not identical) to relative density (Dr)
Density Index
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)
Swell factor (SF)
The physical and mechanical behavior of fine- grained soils is linked to four distinct states:
solid, semisolid, plastic, and liquid, in order of increasing water content.
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 _____
Liquid Limit (LL)
Point C – the water content at which the soil changes from
a plastic to a semi-solid is known as the ___________
Plastic Limit (PL)
If drying is continued beyond the range of water
content for plastic behavior, the soil becomes a ______________.
semisolid
The range of water content over which the soil deforms
plastically is known as the __________
Plasticity Index, PI = LL-PL
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.
soild state
Point D – the water content at which the soil changes from a semisolid to a solid is known as _________
Shrinkage Limit, SL
The range of water content from the plastic limit to the
shrinkage limit for which the soil behaves as a semisolid is
called the _______________
Shrinkage index, SI = PL-SL
He developed a method to describe the consistency of fine-grained soils with varying ω.
Albert Atterberg, 1911
Index parameters are:
a) Plasticity Index (PI= LL-PL)
b) Liquidity Index (LI = ω-PL / LL-PL)
c) Shrinkage Index (SI= PL-SL)
It is the moisture content after 25 blows
or moisture content at which a soil changes from the
liquid state to the plastic state.
Liquid Limit (LL)
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 _________
Casagrande Cup
It is a moisture content in percent at which the soil
crumbles, when rolled into threads of 3.2mm
(1/8”) in diameter.
Plastic Limit (PL)
-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.
Liquid Index, LI
_______________ or simply consistency is analogous to
viscosity in liquids and indicates internal resistance to
forces that tend to deform the soil.
soil consistency
The internal resistance of soil may come from inter-particle
forces (cohesion or adhesion), cementation, inter-particle
friction, and soil suction. (True or False)
True
Consistency changes with water content (True or False)
True
A measure of consistency is provided by the __________
Consistency Index , CI
For soils with a particular mineralogy, the plasticity index
is linearly related to the amount of the clay fraction. This is called ______________
Activity, A= PI/ Clay fraction (%)
_____________ is one of the factors used in identifying expansive or swelling soils.
Activity, A
Classification of Clay based on Activity (A):
A< 0.70 = Inactive
0.70 < A < 1.20 = Normal
A>1.20 = Active
It is the Moisture content (in percent) which the volume
of the soil mass ceases to change.
Shrinkage Limit, SL
Three limits are defined based on the water content
that causes a change of state. These are:
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.
The soil strength is lowest at the liquid state and highest at the solid state. (True or False?)
True
