# Dry Unit Weight

Written by Jerry Ratzlaff on . Posted in Geotechnical Engineering Dry unit weight, abbreviated as $$\gamma_d$$, is the ratio of the weight of soil to the volume of soil or when the soil voids are filled with air and no water.

## Dry Unit Weight formulas

 $$\large{ \gamma_d = \frac{ W_s }{ V_t } }$$ $$\large{ \gamma_d = \frac{ G_s \; \gamma_w }{ V_t } }$$ $$\large{ \gamma_d = \frac{ G_s \; \gamma_w }{ e \;+\;1 } }$$ $$\large{ \gamma_d = \frac{ Y }{ 1 \;+\; w } }$$

### Where:

 Units English Metric $$\large{ \gamma_d }$$  (Greek symbol gamma) = dry unit weight $$\large{ \frac{lbm}{ft^3} }$$ $$\large{ \frac{N}{m^3} }$$ $$\large{ Y }$$ = bulk density $$\large{\frac{lbm}{ft^3}}$$ $$\large{\frac{kg}{m^3}}$$ $$\large{ G_s }$$ = specific gravity of soil $$\large{dimensionless}$$ $$\large{ \gamma_w }$$  (Greek symbol gamma) = unit weight of water $$\large{ \frac{lbm}{ft^3} }$$ $$\large{ \frac{N}{m^3} }$$ $$\large{ e }$$ = void ratio $$\large{dimensionless}$$ $$\large{ V_t }$$ = total volume of soil $$\large{ft^3}$$ $$\large{m^3}$$ $$\large{ w }$$ = water content $$\large{dimensionless}$$ $$\large{ W_s }$$ = weight of soil $$\large{lbf}$$ $$\large{N}$$ 