An 8.5 m thick layer of normally consolidated clay (Cc = 0.15, e₀ = 0.75) has an effective vertical stress of 75 kPa at its mid-depth. A wide fill raises the vertical stress in the clay by 130 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 3.5 m thick layer of normally consolidated clay (Cc = 0.2, e₀ = 1.15) has an effective vertical stress of 135 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.
A 7.5 m thick overconsolidated clay layer has Cc = 0.25, Cr = 0.03 and e₀ = 1.15. At its mid-depth the effective vertical stress is 45 kPa and the preconsolidation pressure is 145 kPa. A new building adds 60 kPa of vertical stress at mid-depth. Find the primary consolidation settlement S in mm.
A 4 m thick overconsolidated clay layer has Cc = 0.4, Cr = 0.02 and e₀ = 0.95. At its mid-depth the effective vertical stress is 100 kPa and the preconsolidation pressure is 210 kPa. A new building adds 85 kPa of vertical stress at mid-depth. Find the primary consolidation settlement S in mm.
A clay layer 3.5 m thick has a coefficient of consolidation cv = 1 m²/year. It lies between two sand layers, so water drains out at the top and the bottom. 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 4 min. In the field the same clay forms a layer 8.5 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 = 318.2 mm
- 2. S = 44.55 mm
- 3. S = 38.51 mm
- 4. S = 10.96 mm
- 5. t = 0.8789 years
- 6. t = 555.9 days
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