A 7 m thick layer of normally consolidated clay (Cc = 0.6, e₀ = 0.8) has an effective vertical stress of 40 kPa at its mid-depth. A wide fill raises the vertical stress in the clay by 85 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 6 m thick layer of normally consolidated clay (Cc = 0.45, e₀ = 1) has an effective vertical stress of 100 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.
A 4 m thick overconsolidated clay layer has Cc = 0.45, Cr = 0.06 and e₀ = 0.65. At its mid-depth the effective vertical stress is 65 kPa and the preconsolidation pressure is 135 kPa. A new building adds 20 kPa of vertical stress at mid-depth. Find the primary consolidation settlement S in mm.
An 8 m thick overconsolidated clay layer has Cc = 0.25, Cr = 0.02 and e₀ = 0.6. At its mid-depth the effective vertical stress is 120 kPa and the preconsolidation pressure is 170 kPa. A new building adds 170 kPa of vertical stress at mid-depth. Find the primary consolidation settlement S in mm.
A clay layer 2 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 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 7.5 m thick has a coefficient of consolidation cv = 3 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 = 1155 mm
- 2. S = 448.8 mm
- 3. S = 16.95 mm
- 4. S = 305.1 mm
- 5. t = 1.512 years
- 6. t = 1.889 years
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