Module 4 : Design of Shallow Foundations
Lecture 19 : Settlement [ Section19.4 : Problems ]
   
 

Degree of Consolidation = 75%

S = 0.0413 ft

t = 14 Years 290 days.

  Problem 2
 

There are two locations 1 & 2 and two footings as shown in the fig. 4.64 and fig. 4.65 Find out the safest position of footings A and B.

for clay layer is 2 x 10-5 m2/t, and is 3 x 10-5 m2/min.

  Ans.:
 

Position 1:

  The settlement of the footing will be due to clay layers beneath the footings. To calculate the final settlement of the footings, the clay layers below the footings are divided into no. of layers, and total settlement will be the summation of the settlement at center of each layer. Refer fig. 4.63. The calculations are given in tabular form in table 4.14
 
Table 4.14 Final settlements for Position 1
 

Layer

Depth z (m)


At center of each layer ( t/m2)

Footing A
Footing B
Footing A
Footing B

Footing A

Footing B

1

1.5

2.2

4.90

0.98

0.0098

0.0008

2

2.5

2.6

2.96

0.77

0.0059

0.0006

3

3.5

3

1.98

0.63

0.0040

0.0005

4

4.5

3.4

1.42

0.52

0.0028

0.0004

5

5.5

3.8

1.07

0.43

0.0021

0.0003

 

 

 

Total settlement(m)

0.02466236

0.00265898

   
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