Geotechnical Engineering

DHARM

26 GEOTECHNICAL ENGINEERING

Water content, w =

() (. .)

.

WW

W

d

d

−

×=

−

100 25 21×

21

100%

=

040

210

100%

.

.

× = 19.05%

Bulk unit weight, γ = W/V = 2.50/150 = 0.0167 N/cm^3

= 16.38 kN/m^3

Dry unit weight, γd = γ

()

.

1 (. )

16 38

+ 1 0 1905

=

w +

kN/m^3

= 13.76 kN/m^3

Also, γd d N/cm^33 kN/m

W

V

L == = =

NM

O

QP

2 10 150 0 014 13 734./..

But γd =

G

e

. w
()

γ

1 +

13.76 =

26 981

1

..

()

×

+e

(1 + e) = 26 981

13 76

..

.

× = 1.854

e = 0.854

Degree of saturation, S = wG

e

=0 1905 2 6×

0 854

..

.

= 0.58

= 58%

Aliter. From the phase-diagram (Fig. 2.6)

V = 150 cc

W = 2.50 N

Wd = Ws = 2.10 N

Water

Solids

V = 150 cm^3

V = 69.23 cmv^3

W = 0.40 Nw

Air

Vw= 40 cm^3

V = 80.77 cms^3 W = 2.10 Ns

W = 2.50 N

Fig. 2.6 Phase diagram (Example 2.9)

Ww = (2.50 – 2.10) N

= 0.40 N

Vw =

Ww

γw

=

040

001

.

.

= 40 cm^3 ,