Volumetric and mass relationship for soil
Soil composed of solid particles with voids, voids will be filled with air or water or both. solid particles composed of different materials particles, the total volume of soil will be the algebraic summation of solid volume Vs and the volume of voids Vv. the volume of voids is the summation of the volume of air void Va and water void Vw. figure one depicting a soil sample with a different volume component of a soil mass.
The phase diagram in figure 2 representing the different component of soil volume on the left side and the masses of the soil at the right side. using these volumes we can find the volumetric ratio's
there is three volumetric ratio's, void ratio, porosity and the degree of saturation. these ratios are important in geotechnical engineering
- Void ratio, e
the value of void ratio e expressed in decimal, it may range from 0 to ∞ , for sands it may range from 0.4 to 1
- The porosity n
porosity value will range from 0 to 100%, it can be shown as
- the degree of saturation S
if the voids inside the soil are filled completely with water S=100%, but if the soil is dry and no water in voids S=0.
in the mass side, the most important ratio for us is the water content, the ratio of water mass to a solid mass.
the water content is the ratio of the mass of water in the soil to the mass of soil grain in a dry condition, not the total mass, w can range from zero for dry soil to several hundred