A 7.5 m thick layer of normally consolidated clay (Cc = 0.4, e₀ = 1.1) has an effective vertical stress of 95 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.
Consolidation settlement worksheet with answers
A 5 m thick normally consolidated clay layer (γsat = 19 kN/m³, Cc = 0.4, e₀ = 0.8) lies below 4.5 m of sand (γ = 17 kN/m³). The water table is at the top of the clay; use γw = 9.81 kN/m³. A wide fill raises the vertical stress throughout the clay by 105 kPa. Treat the layer as one sublayer with the stresses at its mid-depth. Find the primary consolidation settlement S in mm.
A 3 m thick overconsolidated clay layer has Cc = 0.2, Cr = 0.06 and e₀ = 0.9. At its mid-depth the effective vertical stress is 100 kPa and the preconsolidation pressure is 170 kPa. A new building adds 45 kPa of vertical stress at mid-depth. Find the primary consolidation settlement S in mm.
A 7.5 m thick overconsolidated clay layer has Cc = 0.5, Cr = 0.05 and e₀ = 0.6. At its mid-depth the effective vertical stress is 85 kPa and the preconsolidation pressure is 195 kPa. A new building adds 80 kPa of vertical stress at mid-depth. Find the primary consolidation settlement S in mm.
A clay layer 6 m thick has a coefficient of consolidation cv = 1.2 m²/year. It lies between two sand layers, so water drains out at the top and the bottom. For 50% average consolidation the time factor is Tv = 0.197. How many years t does the layer take to reach 50% consolidation?
A clay layer 4.5 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 50% average consolidation the time factor is Tv = 0.197. How many years t does the layer take to reach 50% consolidation?
Answer key
- 1. S = 283.4 mm
- 2. S = 347.7 mm
- 3. S = 15.29 mm
- 4. S = 67.52 mm
- 5. t = 1.478 years
- 6. t = 0.9973 years
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