Week 3. CE322 Volume-Weight Relationship
Week 3. CE322 Volume-Weight Relationship
Week 3. CE322 Volume-Weight Relationship
Properties of
Soil Part 1:
Weight - Volume
Relationship
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Weight – Volume Relationship
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(a) Soil element in natural state; (b) three phases of the soil element
Weight – Volume Relationship
Assuming that the weight of the air is negligible, we can express the total weight of the sample as:
Where:
Va = Volume of air
Vs = Volume of soil
Vw = Volume of water
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Weight – Volume Relationship
Volumetric
Relationship
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Weight – Volume Relationship
The following five volumetric relationship are widely used in soil engineering:
1. VOID RATIO (e)
- is defined as the ratio of the volume of voids to the volume of solids.
2. POROSITY (n)
- is defined as the ratio of the volume of voids to the total volume
Degree of saturation is
generally expressed as a
percentage. It is equal to
zero when the soil is
absolutely dry and 100%
when the soil is fully
saturated.
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Weight – Volume Relationship
The following five volumetric relationship are widely used in soil engineering:
4. PERCENTAGE AIR VOIDS (na)
- is the ratio of the volume of air to the total volume
Weight
Relationship
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Weight – Volume Relationship
The following two weight relationship are widely used in soil engineering:
1. MOISTURE CONTENT (w)
- is also referred to as water content and is defined as the ratio of the weight of water to
the weight of solids in a given volume of soil
The unit weight can also be expressed in terms of the weight of soil solids, the moisture
content, and the total volume:
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Weight – Volume Relationship
Volume-Mass
Relationship
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Weight – Volume Relationship
The volume-mass relationship are in term of mass density
1. BULK MASS DENSITY (ρ)
- is defined as the total mass (M) per unit total volume (V).
The bulk mass density is also known as the wet mass density or
simply bulk density or density. It is expressed in kg/m3, Mg/m3 or
gm/ml. 1Mg/m3 = 1000 kg/m3 = 1 gm/ml
Volume-Weight
Relationship in
terms of Unit
Weights
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Weight – Volume Relationship
The volume-weight relationship are in term of unit weight
1. BULK UNIT WEIGHT
- is defined as the total weight per unit total volume
The bulk unit weight is also known as the total unit weight or the wet
unit weight. It is expressed as N/m3 of kN/m3.
Relationships among
Unit Weight, Void Ratio,
Moisture Content,
and Specific Gravity
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Weight – Volume Relationship
Relationships among Unit Weight, Void Ratio, Moisture Content, and Specific Gravity
To obtain a relationship among unit weight
(or density), void ratio, and moisture
content, let us consider a volume of soil in
which the volume of the soil solids is one.
Void ratio
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Weight – Volume Relationship
Relationships among Unit Weight, Void Ratio, Moisture Content, and Specific Gravity
Degree of saturation
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Weight – Volume Relationship
Relationships among Unit Weight, Void Ratio, Moisture Content, and Specific Gravity
S = 1, thus
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Weight – Volume Relationship
Relationships among Unit Weight, Void Ratio, Moisture Content, and Specific Gravity
Densities
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Weight – Volume Relationship
Relationships among
Unit Weight,
Porosity, and
Moisture Content
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Weight – Volume Relationship
Relationships among Unit Weight, Porosity, and Moisture Content
Porosity
Relative Density
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Weight – Volume Relationship
Relative Density
- commonly used to indicate the in situ denseness or looseness of granular soil. It is
defined as:
where
Dr = relative density, usually given as a percentage
e = in situ void ratio of the soil
emax = void ratio of the soil in the loosest state
emin = void ratio of the soil in the densest state
The values of Dr may vary from a minimum of Qualitative Description of Granular Soil Deposits
0% for very loose soil to a maximum of 100%
for very dense soils. Soils engineers
qualitatively describe the granular soil deposits
according to their relative densities. In-place
soils seldom have relative densities less than
20 to 30%. Compacting a granular soil to a
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where nmax and nmin porosity of the soil in the loosest and densest conditions, respectively.
Substituting these equations, the Dr is:
where
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Yd(min) = dry unit weight in the loosest condition (at a void ratio of emax)
Yd = in situ dry unit weight (at a void ratio of e)
Yd(max) = dry unit weight in the densest condition (at a void ratio of emin)
Weight – Volume Relationship
Thank You!
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