A 7.5 m thick layer of normally consolidated clay (Cc = 0.6, e₀ = 1) has an effective vertical stress of 85 kPa at its mid-depth. A wide fill raises the vertical stress in the clay by 80 kPa. Treat the layer as one sublayer with the stresses at its mid-depth. Find the primary consolidation settlement S in mm.
Consolidation settlement worksheet with answers
A 2 m thick layer of normally consolidated clay (Cc = 0.6, e₀ = 0.85) has an effective vertical stress of 45 kPa at its mid-depth. A wide fill raises the vertical stress in the clay by 30 kPa. Treat the layer as one sublayer with the stresses at its mid-depth. Find the primary consolidation settlement S in mm.
A 4.5 m thick overconsolidated clay layer has Cc = 0.25, Cr = 0.02 and e₀ = 1.15. At its mid-depth the effective vertical stress is 50 kPa and the preconsolidation pressure is 120 kPa. A new building adds 90 kPa of vertical stress at mid-depth. Find the primary consolidation settlement S in mm.
A 3 m thick overconsolidated clay layer has Cc = 0.4, Cr = 0.06 and e₀ = 1.15. At its mid-depth the effective vertical stress is 105 kPa and the overconsolidation ratio is OCR = 3. A new building adds 120 kPa of vertical stress at mid-depth. Find the primary consolidation settlement S in mm.
In a laboratory oedometer test, a clay specimen 25 mm thick, drained at the top and bottom, reaches 50% consolidation in 8 min. In the field the same clay forms a layer 2.5 m thick. It lies between two sand layers, so water drains out at the top and the bottom. How many days t does the field layer take to reach 50% consolidation?
In a laboratory oedometer test, a clay specimen 19 mm thick, drained at the top and bottom, reaches 50% consolidation in 5 min. In the field the same clay forms a layer 4.5 m thick. It lies between two sand layers, so water drains out at the top and the bottom. How many days t does the field layer take to reach 50% consolidation?
Answer key
- 1. S = 648.1 mm
- 2. S = 143.9 mm
- 3. S = 50.95 mm
- 4. S = 27.71 mm
- 5. t = 55.56 days
- 6. t = 194.8 days
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