An 8 m thick layer of normally consolidated clay (Cc = 0.6, e₀ = 1.4) has an effective vertical stress of 70 kPa at its mid-depth. A wide fill raises the vertical stress in the clay by 115 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 4 m thick layer of normally consolidated clay (Cc = 0.35, e₀ = 1.1) has an effective vertical stress of 75 kPa at its mid-depth. A wide fill raises the vertical stress in the clay by 25 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 = 0.4, Cr = 0.05 and e₀ = 1.05. At its mid-depth the effective vertical stress is 45 kPa and the overconsolidation ratio is OCR = 2. A new building adds 190 kPa of vertical stress at mid-depth. Find the primary consolidation settlement S in mm.
A 3 m thick overconsolidated clay layer has Cc = 0.25, Cr = 0.03 and e₀ = 0.9. At its mid-depth the effective vertical stress is 60 kPa and the preconsolidation pressure is 150 kPa. A new building adds 190 kPa of vertical stress at mid-depth. Find the primary consolidation settlement S in mm.
A clay layer 6.5 m thick has a coefficient of consolidation cv = 1.5 m²/year. It lies on impervious rock, with sand above it, so water drains out only at the top. For 60% average consolidation the time factor is Tv = 0.287. How many years t does the layer take to reach 60% consolidation?
In a laboratory oedometer test, a clay specimen 19 mm thick, drained at the top and bottom, reaches 50% consolidation in 10 min. In the field the same clay forms a layer 10 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 = 844.1 mm
- 2. S = 83.29 mm
- 3. S = 487.7 mm
- 4. S = 106.4 mm
- 5. t = 8.084 years
- 6. t = 1924 days
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