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