A 10 m thick layer of normally consolidated clay (Cc = 0.6, e₀ = 0.65) has an effective vertical stress of 125 kPa at its mid-depth. A wide fill raises the vertical stress in 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 6 m thick normally consolidated clay layer (γsat = 18 kN/m³, Cc = 0.6, e₀ = 1.35) lies below 3.5 m of sand (γ = 18 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 150 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 = 0.25, Cr = 0.06 and e₀ = 0.6. At its mid-depth the effective vertical stress is 80 kPa and the preconsolidation pressure is 180 kPa. A new building adds 50 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 = 0.65. At its mid-depth the effective vertical stress is 45 kPa and the overconsolidation ratio is OCR = 2. A new building adds 130 kPa of vertical stress at mid-depth. Find the primary consolidation settlement S in mm.
In a laboratory oedometer test, a clay specimen 25 mm thick, drained at the top and bottom, reaches 50% consolidation in 8 min. In the field the same clay forms a layer 7.5 m thick. It lies between two sand layers, so water drains out at the top and the bottom. How many days t does the field layer take to reach 50% consolidation?
A clay layer 7 m thick has a coefficient of consolidation cv = 4 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 = 1187 mm
- 2. S = 664 mm
- 3. S = 31.63 mm
- 4. S = 379.2 mm
- 5. t = 500 days
- 6. t = 1.736 years
Full step-by-step solutions: practise this topic on examproblems.com.