BASIC QUANTITIES - BULK UNIT MASS, BULK WEIGHT DENSITY, DRY UNIT MASS, DRY WEIGHT DENSITY - SOIL MECHANICS (StudyCivilEngg.com)

BULK UNIT MASS, BULK UNIT WEIGHT

DRY UNIT MASS, DRY UNIT WEIGHT

SUBJECT : SOIL MECHANICS

Bulk Unit Mass or Bulk Mass Density

Bulk unit mass or bulk mass density of a soil mass is defined as the total mass per unit of total volume of the soil mass. It is denoted by the symbol ρ. Thus

ρ = M/V

Here, 

M = (M_w + M_s) or (M_w + M_d) and V = V_a + V_w + V_s 

The bulk unit mass is also known as ‘wet unit mass’ or ‘wet mass density’ or simply ‘bulk density’ or ‘density’. In SI units it is expressed in kg/m³ or g/ml (or g/cc).

Bulk Unit Weight or Bulk Weight Density

Bulk unit weight or Bulk weight density of a soil mass is defined as the total weight per unit of total volume of the soil mass. It is denoted by symbol γ. Thus 

γ = W/V

Here 

W = (W_w + W_s) or (W_w + W_d) and V = V_a + V_w + V_s

The bulk unit weight is also known as ‘wet unit weight’ or ‘total unit weight’ or ‘wet weight density’. In SI units it is expressed in N/m³ or kN/m³, and in metric units it is expressed in kg(f)/m³

Dry Unit Mass or Dry Mass Density 

Dry unit mass or Dry mass density of a soil mass is defined as the mass of solids or solid particles of the soil mass per unit of total volume of the soil mass. It is denoted by symbol ρd. Thus 

ρd = M_s or M_d/V

For determining the dry unit mass of a soil mass the total volume of the soil mass is measured before drying of the soil mass. Since the total volume of a soil mass is a variable with respect to packing of soil grains as well with the water content, the dry unit mass of a soil mass is a relatively variable quantity. The dry unit mass is also known as ‘dry density’. 

The dry unit mass is used to express the denseness of the soil mass. A high value of dry unit mass indicates that the soil mass is in a compact condition. Alike bulk unit mass, dry unit mass is also expressed in kg/m³ or g/ml (or g/cc or g/cm³) in SI units.

Dry Unit Weight or Dry Weight Density

Dry unit weight or Dry weight density of a soil mass is defined as the weight of solids or solid particles of the soil mass per unit of total volume of the soil mass. It is denoted by symbol γd. Thus

γd = W_s or W_d/V

For determining the dry unit weight of a soil mass the total volume of the soil mass is measured before drying of the soil mass. Since the total volume of a soil mass is a variable with respect to packing of soil grains as sell as with the water content, the dry unit weight of a soil mass is a relatively variable quantity. Alike bulk unit weight, dry unit weight is also expressed in N/m³ or kN/m³ in SI units, and in kg(f)/m³ in metric units.

FAQs COVERED IN THIS POST

What is Bulk Unit Mass?
What is Bulk Mass Density?
What is Bulk Unit Weight?
What is Bulk Weight Density?
What is Dry Unit Mass?
What is Dry Mass Density?
What is Dry Unit Weight?
What is Dry Weight Density?
What is Wet Weight Density?
What is the equation for Dry Weight Density?
What is the equation for Bulk Unit Mass?
What is the equation for Bulk Weight Density?
What is the equation for Dry Mass Density?

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