## Density

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

### a. What is Bulk Density (š¯›¾)

The **bulk density** or moist density š¯›¾ is defined as the total weight (W) as a soil mass per unit of its total volume (V). **Thus, š¯›¾ =W/V**

### b. What is Submerged Density (š¯›¾sub)

The submerged density or buoyant unit weight is defined as the submerged weight ( [latex] W_{d} [/latex] )sub of the soil solids per unit of total volume (V) of the soil mass.

Thus, [latex] \gamma_{sub} = \frac{(W_{d})_{sub} }{V} [/latex] It is also expressed as, [latex] \gamma_{sub} = \gamma_{sat} – \gamma_{w} [/latex]

Where

**[latex] \gamma_{w} [/latex] is the density of water and [latex] \gamma_{sat} [/latex] is the saturated density of soil.**

### c. What is Dry Density

The dry density or dry unit weight š¯›¾d is defined as the weight of solids ( [latex] W_{d} [/latex] ) per unit of total volume (V) of the soil mass. **Thus, **[latex] \gamma_{d} = \frac{W_{d} }{V} [/latex]

### 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 ( [latex] W_{sat} [/latex] ) to its total volume (V). **Thus, **[latex] \gamma_{sat} = \frac{W_{sat} }{V} [/latex]

### e. What is the Density of Solids

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

*Read also:*

**Define Specific Gravity, Bulk Specific Gravity, Air Content and Percentage Air Voids**

**What is Porosity, Void Ratio, Water or Moisture Content, And Degree of Saturation of Soil**