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Name: ____________________ Date: ____________
1.Easy
An 8 m thick normally consolidated clay layer (γsat = 19 kN/m³, Cc = 0.5, e₀ = 1.05) lies below 2.5 m of sand (γ = 18.5 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 145 kPa. Treat the layer as one sublayer with the stresses at its mid-depth. Find the primary consolidation settlement S in mm.
sand: Hs = 2.5 m, γ = 18.5 kN/m³clay: H = 8 m, γsat = 19 kN/m³γw = 9.81 kN/m³Cc = 0.5e0 = 1.05Δσ = 145 kPa
S = mm
2.Easy
A 7 m thick normally consolidated clay layer (γsat = 19 kN/m³, Cc = 0.45, e₀ = 1.1) lies below 2.5 m of sand (γ = 19 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 65 kPa. Treat the layer as one sublayer with the stresses at its mid-depth. Find the primary consolidation settlement S in mm.
sand: Hs = 2.5 m, γ = 19 kN/m³clay: H = 7 m, γsat = 19 kN/m³γw = 9.81 kN/m³Cc = 0.45e0 = 1.1Δσ = 65 kPa
S = mm
3.Medium
A 6 m thick overconsolidated clay layer has Cc = 0.2, Cr = 0.06 and e₀ = 1. At its mid-depth the effective vertical stress is 105 kPa and the overconsolidation ratio is OCR = 3. A new building adds 70 kPa of vertical stress at mid-depth. Find the primary consolidation settlement S in mm.
A 6 m thick overconsolidated clay layer has Cc = 0.3, Cr = 0.05 and e₀ = 0.8. At its mid-depth the effective vertical stress is 100 kPa and the preconsolidation pressure is 170 kPa. A new building adds 210 kPa of vertical stress at mid-depth. Find the primary consolidation settlement S in mm.
A clay layer 7 m thick has a coefficient of consolidation cv = 3 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?
A clay layer 5 m thick has a coefficient of consolidation cv = 0.5 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?