Bulk Density

Written by Jerry Ratzlaff on . Posted in Geotechnical Engineering

Bulk density, abbreviated as Y, also called apparent density or volumetric density, is the ratio total weight of soil to the total volume of soil.

Bulk Density formulas

$$\large{ Y = \frac{ W_t }{ V_t } }$$

$$\large{ Y = \frac{ M_t }{ V_t } }$$

$$\large{ Y = \frac{ SG_s \; \left( 1 \;+\; w \right) }{ 1 \;+\; e } \; \rho_w }$$

$$\large{ Y = \frac{ SG_s \; \left( 1 \;+\; w \right) \; \gamma_w }{ 1 \;+\; e } }$$

$$\large{ Y = \frac{ SG_s \;+\; S \; e }{ 1 \;+\; e } \; \rho_w }$$

$$\large{ Y = \frac{ \left( SG_s \;+\; S \; e \right) \; \gamma_w }{ 1 \;+\; e } }$$

Symbol English Metric
$$\large{ Y }$$ = bulk density $$\large{ \frac{lbm}{ft^3} }$$ $$\large{ \frac{kg}{m^3} }$$
$$\large{ S }$$ = degree of saturation (expressed as %) $$\large{dimensionless}$$
$$\large{ \rho_w }$$  (Greek symbol rho) = density of water $$\large{ \frac{lbm}{ft^3} }$$ $$\large{ \frac{kg}{m^3} }$$
$$\large{ SG_s }$$ = specific gravity of soil $$\large{dimensionless}$$
$$\large{ M_t }$$ = total mass of soil $$\large{lbm}$$ $$\large{kg}$$
$$\large{ V_t }$$ = total volume of soil $$\large{ft^3}$$ $$\large{m^3}$$
$$\large{ W_t }$$ = total weight of soil $$\large{lbf}$$ $$\large{N}$$
$$\large{ \gamma_w }$$  (Greek symbol gamma) = unit weight of water $$\large{ \frac{lbm}{ft^3} }$$ $$\large{ \frac{N}{m^3} }$$
$$\large{ e }$$ = void ratio $$\large{dimensionless}$$