# Soil Volume Relation

Written by Jerry Ratzlaff on . Posted in Fluid Dynamics

In soil the quantity of air and water present can vary greatly.  The volume of water will vary between 0 and the volume of voids in the soil.  When all voids or cracks are all filled with water this is called total saturation.  Saturation is expressed degree of saturation or percentage.

### Soil Volume Relation formula

$$\large{ a_c = \frac{V_a}{V_v} }$$

$$\large{ S = \frac{V_w}{V_v}\; 100 }$$

$$\large{ n_a = \frac{V_a}{V}\; 100 }$$

$$\large{ P = \frac{V_v}{V} \;100 }$$

$$\large{ e = V_v + V_s }$$

Where:

$$\large{ a_c }$$ = air content

$$\large{ S }$$ = percentage of saturation

$$\large{ n_a }$$ = percentage air voids

$$\large{ P }$$ = porosity

$$\large{ e }$$ = void ratio

$$\large{ V }$$ = total volume of air, soil solids, and water

$$\large{ V_a }$$ = volume of air

$$\large{ V_s }$$ = volume of soil solids

$$\large{ V_v }$$ = volume of air and water

$$\large{ V_w }$$ = volume of water