A 4 m thick layer of normally consolidated clay (Cc = 0.6, e₀ = 0.95) has an effective vertical stress of 120 kPa at its mid-depth. A wide fill raises the vertical stress in the clay by 95 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 4 m thick layer of normally consolidated clay (Cc = 0.3, e₀ = 1.3) has an effective vertical stress of 95 kPa at its mid-depth. A wide fill raises the vertical stress in the clay by 110 kPa. Treat the layer as one sublayer with the stresses at its mid-depth. Find the primary consolidation settlement S in mm.
A 6 m thick overconsolidated clay layer has Cc = 0.4, Cr = 0.06 and e₀ = 1.05. At its mid-depth the effective vertical stress is 110 kPa and the overconsolidation ratio is OCR = 2.5. A new building adds 140 kPa of vertical stress at mid-depth. Find the primary consolidation settlement S in mm.
A 5.5 m thick overconsolidated clay layer has Cc = 0.3, Cr = 0.06 and e₀ = 1.1. At its mid-depth the effective vertical stress is 115 kPa and the preconsolidation pressure is 225 kPa. A new building adds 40 kPa of vertical stress at mid-depth. Find the primary consolidation settlement S in mm.
A clay layer 4.5 m thick has a coefficient of consolidation cv = 5 m²/year. It lies on impervious rock, with sand above it, so water drains out only at the top. For 70% average consolidation the time factor is Tv = 0.403. How many years t does the layer take to reach 70% consolidation?
A clay layer 5.5 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 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 = 311.7 mm
- 2. S = 174.3 mm
- 3. S = 62.61 mm
- 4. S = 20.37 mm
- 5. t = 1.632 years
- 6. t = 1.429 years
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