Compaction, Consolidation and Exploration
JKSSB Junior Engineer (Civil) · Soil Mechanics · 13 practice questions with answers and explanations: 10 Easy, 2 Medium, 1 Hard.
Sample questions
Sample Easy question 1
With an increase in the compaction effort, the maximum dry density:
- Decreases and the optimum moisture content increases
- Stays the same
- Increases and the optimum moisture content decreases
- Increases and the optimum moisture content increases
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Answer: C. More effort packs the grains closer with less water.
Sample Easy question 2
The zero air voids line on a compaction diagram shows:
- The dry density at full saturation for each water content
- The liquid limit
- The maximum dry density at each moisture content
- The optimum moisture content
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Answer: A. The compaction curve always lies below it.
Sample Easy question 3
Primary consolidation of a clay is the settlement due to:
- The compression of the soil particles
- The loss of air from the soil
- The creep of the soil skeleton
- The squeezing out of water from the pores
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Answer: D. Secondary consolidation is the later, slower creep.
Sample Medium question 4
The time factor Tv for 50% consolidation in Terzaghi's theory is about:
- 0.197
- 0.848
- 1.0
- 0.5
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Answer: A. For 90% consolidation, Tv = 0.848.
Sample Medium question 5
For a strip footing on a saturated clay with φ = 0 and c = 40 kPa, Terzaghi's ultimate bearing capacity with Nc = 5.7 is about:
- 40 kPa
- 228 kPa
- 114 kPa
- 456 kPa
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Answer: B. qu = c × Nc = 40 × 5.7 = 228 kPa (at surface level).
Sample Hard question 6
A clay layer 4 m thick has Cc = 0.3, e₀ = 0.9, an initial effective stress of 100 kPa and an increase of 100 kPa. The primary settlement is about:
- 0.63 m
- 0.19 m
- 0.38 m
- 0.1 m
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Answer: B. Sc = Cc H ÷ (1 + e₀) × log₁₀ ((σ₀ + Δσ) ÷ σ₀) = 0.632 × 0.301 = 0.19 m.