A 5.5 m thick layer of normally consolidated clay (Cc = 0.25, e₀ = 1.1) has an effective vertical stress of 90 kPa at its mid-depth. A wide fill raises the vertical stress in the clay by 75 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 m thick layer of normally consolidated clay (Cc = 0.35, e₀ = 1.3) has an effective vertical stress of 105 kPa at its mid-depth. A wide fill raises the vertical stress in the clay by 55 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 = 0.5, Cr = 0.04 and e₀ = 0.7. At its mid-depth the effective vertical stress is 110 kPa and the preconsolidation pressure is 180 kPa. A new building adds 30 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 = 0.25, Cr = 0.02 and e₀ = 0.85. At its mid-depth the effective vertical stress is 100 kPa and the overconsolidation ratio is OCR = 1.5. A new building adds 120 kPa of vertical stress at mid-depth. Find the primary consolidation settlement S in mm.
A clay layer 9.5 m thick has a coefficient of consolidation cv = 0.5 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?
A clay layer 4.5 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 70% average consolidation the time factor is Tv = 0.403. How many years t does the layer take to reach 70% consolidation?
Answer key
- 1. S = 172.4 mm
- 2. S = 55.67 mm
- 3. S = 18.48 mm
- 4. S = 85.33 mm
- 5. t = 102.3 years
- 6. t = 1.36 years
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