The Volume Weight relationships are in terms of unit weights.

The weight of soil per unit volume is known as unit weight(or specific weight)

(1) BULK UNIT WEIGHT:

The bulk unit weight $\gamma$ is ratio of total unit weight to the total volume.

Bulk unit weight is also known as total weight or wet unit weight.

$\gamma_b = \dfrac{W}{V}$

SI unit:- N/$m^3$ or kN/$m^3$

some text:- $\gamma_b$ , $\gamma_t$

(2) DRY UNIT WEIGHT:

It is ratio of weights of solids to the total volume

$\gamma_d = \dfrac{W_s}{V}$

(3) SATURATED UNIT WEIGHT:

The saturated unit weight $(\gamma_{sat})$ is the bulk unit weight when the soil is fully saturated.

$\gamma_{sat} = \dfrac{W_{sat}}{V}$

(4) SUBMERGED UNIT WEIGHT: $\gamma^!$

Submerged unit weight is defined as ratio of Submerged weight to the total volume.

Thus,$\gamma^! = \dfrac{W_{sub}}{V}$

OR

$\gamma^! = \gamma_{sat} - \gamma_w$

(5) UNIT WEIGHT OF SOLID:- $\gamma_s$

The unit weight of solid $\gamma_s$ is equal to the ratio of weight of solids to the total volume of solids.

$\boxed{\gamma_s = \dfrac{W_s}{V_s}}$