A 6 m thick normally consolidated clay layer (γsat = 18 kN/m³, Cc = 0.25, e₀ = 1.2) lies below 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 140 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 m thick layer of normally consolidated clay (Cc = 0.6, e₀ = 1.35) 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 2.5 m thick overconsolidated clay layer has Cc = 0.4, Cr = 0.02 and e₀ = 0.6. At its mid-depth the effective vertical stress is 85 kPa and the preconsolidation pressure is 125 kPa. A new building adds 35 kPa of vertical stress at mid-depth. Find the primary consolidation settlement S in mm.
A 6 m thick overconsolidated clay layer has Cc = 0.5, Cr = 0.05 and e₀ = 1. At its mid-depth the effective vertical stress is 65 kPa and the preconsolidation pressure is 165 kPa. A new building adds 130 kPa of vertical stress at mid-depth. Find the primary consolidation settlement S in mm.
A clay layer 9 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 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 2.5 m thick has a coefficient of consolidation cv = 5 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 = 243.8 mm
- 2. S = 255.9 mm
- 3. S = 4.68 mm
- 4. S = 169.5 mm
- 5. t = 7.654 years
- 6. t = 0.1772 years
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