Under load, the void ratio of a submerged saturated clay decreases from 1.00 to 0.92. What will be the ultimate settlement of the 2 m thick clay due to compaction?
- A20 mm
- B40 mm
- C80 mmCorrect
- D160 mm
Solution
Concept
Consolidation settlement from void ratio
Formula
ΔH = H × Δe / (1 + e₀)
Step-by-step solution
1. Δe = 1.00 − 0.92 = 0.08; e₀ = 1.00. 2. ΔH = 2000 mm × 0.08 / (1 + 1.00) = 80 mm.
Explanation
Settlement of a clay layer is the change in void ratio divided by the initial volume factor (1 + e₀), multiplied by the thickness of the layer.
Shortcut
Settlement = H Δe/(1 + e₀) = 2000 × 0.04.
Common mistake
Dividing by e₀ alone or forgetting the 1 in (1 + e₀).
Correct answer: C) 80 mm