Question

Consider a clay deposit having a thickness of 15 cm and a void ratio of 1. After going under the settlement, its final void ratio becomes 0.4. Which of the following option gives the correct value for thickness of its settlement layer?
1. 2.4 cm
2. 0.24 cm
3. 4.5 cm
4. 0.45 cm

Answer 1

Correct Answer - Option 3 : 4.5 cm

Concepts:

The relationship between change in thickness of soli due to settlement and change in void ratio of soil is given as:

\(\frac{\Delta H}{H} = \frac{\Delta e}{1 + e_o}\)

Where,

ΔH is the change in thickness of soil

H is the initial thickness

Δe is magnitude of change in void ratio of soil

e_o is the initial void ratio

Calculation:

Initial thickness, H = 15 cm

Initial Void ratio, e_o = 1

Final Void ratio, e_f = 0.4

Change in Void ratio, Δe = 1 – 0.4 = 0.6

Substituting these values in above given equation, we get

\(\frac{\Delta H}{15} = \frac{0.6}{1 + 1}\)

∴ ΔH = 4.5 cm