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Name: ____________________ Date: ____________
1.Easy
A 3 m thick normally consolidated clay layer (γsat = 19.5 kN/m³, Cc = 0.4, e₀ = 1.3) 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.
sand: Hs = 3.5 m, γ = 18 kN/m³clay: H = 3 m, γsat = 19.5 kN/m³γw = 9.81 kN/m³Cc = 0.4e0 = 1.3Δσ = 150 kPa
S = mm
2.Easy
A 2 m thick layer of normally consolidated clay (Cc = 0.35, e₀ = 1.05) has an effective vertical stress of 115 kPa at its mid-depth. A wide fill raises the vertical stress in the clay by 45 kPa. Treat the layer as one sublayer with the stresses at its mid-depth. Find the primary consolidation settlement S in mm.
H = 2 mCc = 0.35e0 = 1.05σ′0 = 115 kPaΔσ = 45 kPa
S = mm
3.Medium
A 4.5 m thick overconsolidated clay layer has Cc = 0.45, Cr = 0.02 and e₀ = 0.6. At its mid-depth the effective vertical stress is 75 kPa and the preconsolidation pressure is 135 kPa. A new building adds 180 kPa of vertical stress at mid-depth. Find the primary consolidation settlement S in mm.
A 3 m thick overconsolidated clay layer has Cc = 0.25, Cr = 0.05 and e₀ = 0.7. At its mid-depth the effective vertical stress is 120 kPa and the preconsolidation pressure is 190 kPa. A new building adds 210 kPa of vertical stress at mid-depth. Find the primary consolidation settlement S in mm.
A clay layer 6.5 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?
A clay layer 3 m thick has a coefficient of consolidation cv = 2 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?