# What is Bulk, Submerged, Dry and Saturated Density of Solids of Soil

## Density

The density or unit weight of a soil mass is defined as its weight per unit volume.

### a. What is Bulk Density (𝛾)

The bulk density or moist density 𝛾 is defined as the total weight (W) as a soil mass per unit of its total volume (V).
Thus, 𝛾 =W/V

### b. What is Submerged Density (𝛾sub)

The submerged density or buoyant unit weight is defined as the submerged weight ( $W_{d}$ )sub of the soil solids per unit of total volume (V) of the soil mass.
Thus, $\gamma_{sub} = \frac{(W_{d})_{sub} }{V}$

It is also expressed as, $\gamma_{sub} = \gamma_{sat} - \gamma_{w}$
Where $\gamma_{w}$ is the density of water and  $\gamma_{sat}$  is the saturated density of soil.

### c. What is Dry Density

The dry density or dry unit weight 𝛾d is defined as the weight of solids ( $W_{d}$ ) per unit of total volume (V) of the soil mass.
Thus, $\gamma_{d} = \frac{W_{d} }{V}$

### d. What is Saturated Density

When the soil mass is saturated, its bulk density is called the saturated density. Thus saturated density is the ratio of the total weight of a saturated soil sample ( $W_{sat}$ ) to its total volume (V).
Thus, $\gamma_{sat} = \frac{W_{sat} }{V}$

### e. What is the Density of Solids

The density or unit weight of soil solids Is the weight of soil solids ( $W_{d}$ ) per unit volume of the solids ( $V_{s}$ ).
Thus, $\gamma_{s} = \frac{W_{d} }{V_{s}}$