HOMEWORK SOLUTION

 

HW #9

 

GEOTECHNICAL ENGINEERING I

 

(Question no. 7.16, 7.18, 7.22, ..Al-Khafaji textbook)

 

 


10

 

60

 

10

 

10

 
7.16

 

 

 

 

 

 

 

 

 

 

 

 


 

 

Question:

 

Determine the ultimate consolidation settlement caused by the placement of 5 ft of fill on top of the above profile. (assume sm fill = 110.4 pcf)

 

Solution:

due to the fill = 110.4 x 5 = 552 psf

 

7.18

e=1.00

e=0.9

 

t50 = 12 min (two way drainage)

d1 = 25.2 mm

d2 = 24.3 min T50 = 0.197

 

Question:

 

Determine the coefficient of permeability (k) and the compression Index (Cc) for the clay.

 

Solution:

 

 


7.22                  footing(rectangular)=2.4m x 1.8m

 

(L/B=2.4/1.8=1.33<10)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


Question:

 

Settlement after 1 year.

 

Solution:

 

Iz (0) = 0.1

Iz (2B) = 0 2B=2x1.8=3.6m

Iz (B/2) = 0.5+0.1

 

= 0.5+0.1

 

svp (B/2) = 14.9x(0.9) = 13.41


 

Depth (m)

qc

Es=2.5xqc (MN/m2)

sm (kN/m3)

0.6-1.2

2.85

7.125

14.9

1.2-1.8

3.14

7.85

14.9

1.8-2.1

5.6

14

16.5

2.1-2.4

8.33

20.825

16.5

2.4-3.0

5

12.5

16.5

3.0-3.6

7.37

18.425

18.9

3.6-4.2

12.5

31.25

18.9

 

 

 

Dz (m)

Iz

E (MN/m2)

(Iz/E)xDz (m3/MN)

0.6

0.38

7.125

0.032

0.6

0.93

7.85

0.071

0.3

0.774

14

0.017

0.3

0.67

20.825

0.0097

0.6

0.516

12.5

0.0248

0.6

0.31

18.425

0.01

0.6

0.1

31.25

0.0019

 

Total = 0.1661 m3/MN

= 1.661x10-4 m3/kN

 

t=1 year

= 1.2

 

 

 

Settlement (r)=

= 0.98 x 1.2 x 254.6 x 0.0001661

= 49.73 x 10-3 m

= 49.73 mm ~ 5 cm