Question 1:
A shallow foundation on a deposit of sandy soil is 3 in wide and 3 m long. It will be located at a depth of 1.5 m below the ground surface. The variations of the cone tip resistance and unit weight with depth are idealized as given in the table below. The water table is 1.5 m below ground level. If the working load to be supported by the foundation is 2600 kN, use the Sctunertmann's method to estimate the settlement of the foundation for the following conditions:
(a) Immediately after construction
(b) 10 years after construction
|
Depth (m)
|
ci, (MPa)
|
Unit weight (kN/m3)
|
|
0-1.5
|
8.62
|
16.5
|
|
1.5-3.0
|
8.62
|
18.0
|
|
3.0-4.5
|
11.5
|
18.0
|
|
4.5-7.5
|
19.2
|
18.5
|
|
Below 7.5
|
28.7
|
19.0
|
Question 2:
A flexible rectangular raft foundation 4 m wide and 5 m long is to be constructed on the surface of a 8-m thick clay later and will support a uniform pressure of 60 kN/m2. The water table is at 2 m below ground level. The bulk unit weight of the clay, above and below the water table, is 19.8 kN/m3. An oedometer test conducted on a specimen of the clay gives the following results:
|
Applied pressure (kN/m2)
|
Thickness of specimen (mm)
|
|
0
|
20
|
|
25
|
19.806
|
|
50
|
19.733
|
|
100
|
19.600
|
|
200
|
19.357
|
|
400
|
18.835
|
The initial water content of the specimen is 30% and the specific gravity is 2.7. Using the test results determine the maximum consolidation settlement of the raft foundation.