Void Ratio

Written by Jerry Ratzlaff on . Posted in Geotechnical Engineering

partially saturated soil 1Void ratio, abbreviated as e, a dimensionless number, is the ratio of the volume of voids to the volume of solids.

 

Void Ratio formulas

\(\large{ e = \frac {V_v} {V_s } }\)   
\(\large{ e = \frac { V_v }{ V_t \;-\; V_v } }\)  
\(\large{ e = \frac { n }{ 1 \;-\; n } }\)  
\(\large{ e = \frac { w \; G_s }{ S } }\)  
\(\large{ e =    \left[ \frac { G_s \; \left( 1 \;+\; w \right) \; \gamma_w   }{ Y } \right] \; -1    }\)  

Where:

 Units English Metric
\(\large{ e }\) = void ratio \(\large{dimensionless}\)
\(\large{ Y }\) = bulk density \(\large{\frac{lbm}{ft^3}}\) \(\large{\frac{kg}{m^3}}\)
\(\large{ S }\) = degree of saturation (expressed as %) \(\large{dimensionless}\)
\(\large{ n }\) = porosity \(\large{dimensionless}\) 
\(\large{ G_s }\) = specific gravity of soil \(\large{dimensionless}\)
\(\large{ V_t } \) = total volume of soil \(\large{ft^3}\)  \(\large{m^3}\)
\(\large{  \gamma_w } \)  (Greek symbol gamma) = unit weight of water  \(\large{lbf}\)  \(\large{N}\)  
\(\large{ V_s }\) = volume of solids \(\large{ft^3}\)  \(\large{m^3}\)
\(\large{ V_v} \) = volume of voids \(\large{ft^3}\)  \(\large{m^3}\)
\(\large{ w }\) = water content (% moisture contemt)  \(\large{dimensionless}\)

 

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Tags: Volume Equations Soil Equations Geotechnical Equations