THREE PHASES OF SOIL SOIL CONSISTS OF 1.WATER 2.AIR 3.SOLID PARTICLES

1. By :- Shekhar Mehta

2. SOLID PARTICLES WATER AIR
» For dry soil mass, the voids are filled with only air
» For fully saturated soil mass, voids are completely filled
with water

3. » All particles of soil are having same size & density.
» Soil is partly dry & partly saturated.
» Moisture is uniformly distributed in the soil mass.
» Air in soil mass has no weight.

4. » Partly dry & partly saturated soil 3 phases (solid,
water, air) 3 phase dia.
» Fully dry soil 2 phases (solid & air) 2 phase dia.
» Fully saturated soil 2 phases (solid & water) 2
phase dia.
 THREE PHASES OF SOIL :-

8. » WATER CONTENT/MOISTURE CONTENT (W):
w = Mw x 100
Ms
where, Mw = weight of water
Ms = weight of dry soil
» BULK UNIT WEIGHT (Yb):
ϒb = W
V
where, W = total weight of soil mass
V = vol. of soil mass

9. » DRY UNIT WEIGHT (ϒd):
ϒd = Wd
V
where, Wd = total weight of soil solid
» SATURATED UNIT WEIGHT (ϒsat):
ϒsat = Wsat
V
» SUBMERGED UNIT WEIGHT (ϒsub):
ϒsub = (Wd)sub &
V
ϒsub = ϒsat – ϒw
» UNIT WEIGHT OF SOLIDS (ϒS):
ϒS = WS VS

10. » SPECIFIC GRAVITY (G):
G = WS WW OR ϒS ϒW
where, Ws = weight of given vol. of soil solid
Ww = weight of equal vol. of distilled
water
It has no unit.
» VOID RATIO (e):
e = VV VS
where, Vv = vol. of voids
Vs = vol. of solid
» POROSITY (n):
n = Vv V

11. » DEGREE OF SATURATION (Sr):
Sr = VW VV
For fully saturated soil, Sr = 1 &
for fully dry soil, Sr = 0
» AIR CONTENT (aC):
aC = Va VV = 1 – Sr
where, Va = vol. of air voids
» PERCENTAGE AIR VOIDS (na):
na = Va V

12. » DENSITY INDEX/ RELATIVE INDEX (ID):
ID = emax – e
emax – emin
where, emax = void ratio in loosest state
emin = void ratio in densest state
e = natural void ratio of the deposit
» BULK DENSITY (ρb):
ρb = M V
where, M = total mass
» DRY DENSITY (ρd):
ρd = Md V

13. » SATURATED DENSITY (ρsat):
ρsat = Msat V
» SUBMERGED DENSITY (ρsub):
ρsub = Msub V
= ρsat – ρw
where, ρw = density of water
= 1000 kg/ m3

14. » e = n OR n = e
1 – n 1 – e
» e = w . G
Sr
» ϒb = (G + e . Sr)ϒw
1 + e
» ϒd = ϒb
1 +w

15. » DEFINATION :-
˃ Those properties of soil which are used in the
identification & classification of soils are called index
properties.

16. » The various index properties of soils are :-
˃ Water content
˃ In-situ density
˃ Specific gravity
˃ Particle size
˃ Consistency
˃ Density Index