A 7 m thick layer of normally consolidated clay (Cc = 0.3, e₀ = 1.2) has an effective vertical stress of 50 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.
Consolidation settlement worksheet with answers
A 9 m thick layer of normally consolidated clay (Cc = 0.15, e₀ = 0.95) has an effective vertical stress of 105 kPa at its mid-depth. A wide fill raises the vertical stress in the clay by 65 kPa. Treat the layer as one sublayer with the stresses at its mid-depth. Find the primary consolidation settlement S in mm.
A 7 m thick overconsolidated clay layer has Cc = 0.4, Cr = 0.06 and e₀ = 0.95. At its mid-depth the effective vertical stress is 90 kPa and the preconsolidation pressure is 200 kPa. A new building adds 170 kPa of vertical stress at mid-depth. Find the primary consolidation settlement S in mm.
A 3.5 m thick overconsolidated clay layer has Cc = 0.2, Cr = 0.06 and e₀ = 0.6. At its mid-depth the effective vertical stress is 120 kPa and the preconsolidation pressure is 150 kPa. A new building adds 15 kPa of vertical stress at mid-depth. Find the primary consolidation settlement S in mm.
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 7.5 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?
A clay layer 6 m thick has a coefficient of consolidation cv = 1.5 m²/year. It lies between two sand layers, so water drains out at the top and the bottom. For 80% average consolidation the time factor is Tv = 0.567. How many years t does the layer take to reach 80% consolidation?
Answer key
- 1. S = 519.3 mm
- 2. S = 144.9 mm
- 3. S = 238.3 mm
- 4. S = 6.714 mm
- 5. t = 488.3 days
- 6. t = 3.402 years
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