An 8 m thick layer of normally consolidated clay (Cc = 0.4, e₀ = 1.2) has an effective vertical stress of 80 kPa at its mid-depth. A wide fill raises the vertical stress in the clay by 120 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 5 m thick layer of normally consolidated clay (Cc = 0.2, e₀ = 1.3) has an effective vertical stress of 150 kPa at its mid-depth. A wide fill raises the vertical stress in the clay by 150 kPa. Treat the layer as one sublayer with the stresses at its mid-depth. Find the primary consolidation settlement S in mm.
A 5.5 m thick overconsolidated clay layer has Cc = 0.2, Cr = 0.03 and e₀ = 0.8. At its mid-depth the effective vertical stress is 50 kPa and the overconsolidation ratio is OCR = 1.5. A new building adds 190 kPa of vertical stress at mid-depth. Find the primary consolidation settlement S in mm.
A 2.5 m thick overconsolidated clay layer has Cc = 0.35, Cr = 0.05 and e₀ = 0.65. At its mid-depth the effective vertical stress is 50 kPa and the preconsolidation pressure is 80 kPa. A new building adds 20 kPa of vertical stress at mid-depth. Find the primary consolidation settlement S in mm.
In a laboratory oedometer test, a clay specimen 19 mm thick, drained at the top and bottom, reaches 50% consolidation in 6 min. In the field the same clay forms a layer 8 m thick. It lies on impervious rock, with sand above it, so water drains out only at the top. How many days t does the field layer take to reach 50% consolidation?
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 6 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 = 578.8 mm
- 2. S = 130.9 mm
- 3. S = 324.8 mm
- 4. S = 11.07 mm
- 5. t = 2955 days
- 6. t = 320 days
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