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LOSITAÑO, MARVIN JOHN CANTES BU BSCE 4A

ASSIGNMENT #1 (CE411c)

3.1) For a given soil, show that

a. γsat = γd + nγw

b. γsat = n γw

where wsat = moisture content at saturated state

c. γd =

sol’n:

a) γsat = γd + nγw

since:

γsat = γw γd = n=

so:

γw = + γw

=

γw = γw

b) γsat = n γw

where wsat = moisture content at saturated state

since:

γsat = γw Gsw = eS (but since s = 1) w =

γw = n γw

= γw

= γw

γw = γw

c) γd =

from :

γd = Gsw = eS

=

=

=

3.3) The moist mass of 2.8 x 10-3 m3 of soil is 5.53 kg. If the moisture content is 10 % and the specific gravity of soil solids is 2. 72, determine the following:

a. Moist density

b. Dry density

c. Void ratio

d. Porosity

e. Degree of Saturation

f. Volume occupied by water

sol’n:

a) ρb = m/v

= 5.53 kg/2.8 x 10-3 m3

= 1975 kg/m3

For b and c:

ρb = Gsρw

1975 kg/m3 = (2.72)(1000kg/m3)

1975 + 1975e = 2992

e = 0.515

ρdry =

=

ρdry = 1795.38

d) n = x 100%

= x 100%

n = 34%

e) Gsw = eS

S =

= x 100%

S = 52.8%

f) e =

Vs =

V = Vv + Vs

V = eVs + Vs = Vs(1 + e) =

Ms = ρsVs Vs = 1.848 x 10-3m3

= GsρwaterVs

= (2.72)(1000kg/m3)( 1.848 x 10-3m3)

= 5.027 kg

MT = Ms + Mw + Ma ρwater = Mw/Vw

Mw = 5.53 kg – 5.027 kg Vw = 0.503 kg/(1000...