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Name: ____________________ Date: ____________
1.Easy
A 4 m thick normally consolidated clay layer (γsat = 19.5 kN/m³, Cc = 0.45, e₀ = 0.85) lies below 6 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 85 kPa. Treat the layer as one sublayer with the stresses at its mid-depth. Find the primary consolidation settlement S in mm.
sand: Hs = 6 m, γ = 17.5 kN/m³clay: H = 4 m, γsat = 19.5 kN/m³γw = 9.81 kN/m³Cc = 0.45e0 = 0.85Δσ = 85 kPa
S = mm
2.Easy
A 2.5 m thick layer of normally consolidated clay (Cc = 0.4, e₀ = 1.15) has an effective vertical stress of 45 kPa at its mid-depth. A wide fill raises the vertical stress in 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 3.5 m thick overconsolidated clay layer has Cc = 0.25, Cr = 0.02 and e₀ = 0.9. At its mid-depth the effective vertical stress is 50 kPa and the preconsolidation pressure is 120 kPa. A new building adds 10 kPa of vertical stress at mid-depth. Find the primary consolidation settlement S in mm.
A 3.5 m thick overconsolidated clay layer has Cc = 0.2, Cr = 0.04 and e₀ = 1.1. At its mid-depth the effective vertical stress is 95 kPa and the preconsolidation pressure is 165 kPa. A new building adds 120 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 = 2 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?
In a laboratory oedometer test, a clay specimen 20 mm thick, drained at the top and bottom, reaches 50% consolidation in 12 min. In the field the same clay forms a layer 3 m thick. It lies on impervious rock, with sand above it, so water drains out only at the top. How many days t does the field layer take to reach 50% consolidation?