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Name: ____________________ Date: ____________
1.Easy
A 9 m thick normally consolidated clay layer (γsat = 19.5 kN/m³, Cc = 0.4, e₀ = 1.05) lies below 5 m of sand (γ = 17.5 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 = 5 m, γ = 17.5 kN/m³clay: H = 9 m, γsat = 19.5 kN/m³γw = 9.81 kN/m³Cc = 0.4e0 = 1.05Δσ = 150 kPa
S = mm
2.Easy
An 8.5 m thick layer of normally consolidated clay (Cc = 0.6, e₀ = 0.8) has an effective vertical stress of 85 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 = 8.5 mCc = 0.6e0 = 0.8σ′0 = 85 kPaΔσ = 45 kPa
S = mm
3.Medium
A 2 m thick overconsolidated clay layer has Cc = 0.25, Cr = 0.03 and e₀ = 0.6. At its mid-depth the effective vertical stress is 95 kPa and the preconsolidation pressure is 215 kPa. A new building adds 50 kPa of vertical stress at mid-depth. Find the primary consolidation settlement S in mm.
A 7 m thick overconsolidated clay layer has Cc = 0.3, Cr = 0.05 and e₀ = 1.1. At its mid-depth the effective vertical stress is 90 kPa and the preconsolidation pressure is 210 kPa. A new building adds 170 kPa of vertical stress at mid-depth. Find the primary consolidation settlement S in mm.
A clay layer 5 m thick has a coefficient of consolidation cv = 1.5 m²/year. It lies on impervious rock, with sand above it, so water drains out only at the top. 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 8.5 m thick has a coefficient of consolidation cv = 1.2 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?