Answer:
A. 0.4
B. 1.003
C. 0.83
Explanation:
The void ratio of a mixture is defined as the ratio of the volume of voids to volume of solids.
Total volume of soil = 1/30 ft3
= 1 ft3/30 * 0.0283 m3/1 ft3
= 9.43 x 10^-4 m3
Mass of water is in the soil = 20% * 4.8
= 0.96 pounds of water
= 0.96 * 0.454
= 0.44 kg
SG = density of substance/density of water
= 2.66 * 1 kg/l
Density of the soil = 2.660 kg/l
Mass of solid = 80 %
= 80% * 4.8 * 0.454
= 1.74 kg
Volume of solids = mass/density
= 1.74/2.66
= 6.63 l
= 6.63 x 10^-4 m3.
The volume of voids is found by adding the volume of water and the volume of air.
Total volume of soil = volume of (solids + voids)
9.43 x 10^-4 = 6.63 x 10^-4 + voids
Volume of voids = 2.8 x 10^-4 m3
A.
Void ratio = volume of void : volume of solids
= 2.8 : 6.63
= 0.4
B.
Y = (1 + w) * Gs * Yw * (1 + e)
Y = moist unit weight
Yw = unit weight of water
w = moisture content of the material
Gs = pecific gravity of the solid
e = void ratio
= (1 + 0.2) * 2.66 * 0.44 * (1 + 0.4)
= 1.003.
C.
gd = Y/(1 + w)
Or
= Gs * Yw * 1/(1 + e)
= 0.83.
