2) Soil Phase Relations

2) Soil Phase Relations

1. Weight and unit weight

   • Weight
     • W=mg
   • Unit weight
     • γ=ρg

2. Specific Gravity

   • Gs=γ/γw
   • Gs=2.65 for most soils

3. Volumetric ratios

   • Void ratio e
     • e=Vv/Vs
   • Porosity n
     • n=Vv/Vt

4. Degree of Saturaion Sr

   • Sr=Vw/Va+Vw

5. Moisture content m

   • m=Ww/Ws

6. Unit weights

   • Bulk unit weight γb
     • γb=W/V
   • Saturated unit weight γsat
     • γw(Gs+e)/1+e
   • Dry unit weight
     • γdry= γwGs/1+e
   • Submerged unit weight
     • γ`=γsat-γw

7. Typical bulk densities

   • Sand&Gravel 1.6-2.2
   • Silt 1.6-2.0
   • Soft Clay 1.7-2.0
   • Stiff Clay 1.7-2.3
   • Peat 1.0-1.4
   • Weak rock 2.0-2.3
   • Hard rock 2.4-2.7