A 6 m thick layer of normally consolidated clay (Cc = 0.5, e₀ = 0.9) has an effective vertical stress of 80 kPa at its mid-depth. A wide fill raises the vertical stress in the clay by 50 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 2.5 m thick layer of normally consolidated clay (Cc = 0.15, e₀ = 0.9) has an effective vertical stress of 120 kPa at its mid-depth. A wide fill raises the vertical stress in the clay by 125 kPa. Treat the layer as one sublayer with the stresses at its mid-depth. Find the primary consolidation settlement S in mm.
A 2 m thick overconsolidated clay layer has Cc = 0.45, Cr = 0.02 and e₀ = 1.1. At its mid-depth the effective vertical stress is 110 kPa and the overconsolidation ratio is OCR = 2.5. A new building adds 150 kPa of vertical stress at mid-depth. Find the primary consolidation settlement S in mm.
A 6.5 m thick overconsolidated clay layer has Cc = 0.4, Cr = 0.06 and e₀ = 1.1. At its mid-depth the effective vertical stress is 40 kPa and the preconsolidation pressure is 70 kPa. A new building adds 130 kPa of vertical stress at mid-depth. Find the primary consolidation settlement S in mm.
A clay layer 9 m thick has a coefficient of consolidation cv = 3 m²/year. It lies on impervious rock, with sand above it, so water drains out only at the top. For 80% average consolidation the time factor is Tv = 0.567. How many years t does the layer take to reach 80% consolidation?
In a laboratory oedometer test, a clay specimen 20 mm thick, drained at the top and bottom, reaches 50% consolidation in 5 min. In the field the same clay forms a layer 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 = 332.9 mm
- 2. S = 61.18 mm
- 3. S = 7.116 mm
- 4. S = 522.2 mm
- 5. t = 15.31 years
- 6. t = 217 days
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