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Name: ____________________ Date: ____________
1.Easy
A 3 m thick normally consolidated clay layer (γsat = 17.5 kN/m³, Cc = 0.45, e₀ = 1.3) lies below 3.5 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 115 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 = 17.5 kN/m³clay: H = 3 m, γsat = 17.5 kN/m³γw = 9.81 kN/m³Cc = 0.45e0 = 1.3Δσ = 115 kPa
S = mm
2.Easy
A 7 m thick layer of normally consolidated clay (Cc = 0.3, e₀ = 1.35) has an effective vertical stress of 130 kPa at its mid-depth. A wide fill raises the vertical stress in the clay by 110 kPa. Treat the layer as one sublayer with the stresses at its mid-depth. Find the primary consolidation settlement S in mm.
H = 7 mCc = 0.3e0 = 1.35σ′0 = 130 kPaΔσ = 110 kPa
S = mm
3.Medium
A 5 m thick overconsolidated clay layer has Cc = 0.2, Cr = 0.06 and e₀ = 1. At its mid-depth the effective vertical stress is 60 kPa and the preconsolidation pressure is 180 kPa. A new building adds 25 kPa of vertical stress at mid-depth. Find the primary consolidation settlement S in mm.
A 4.5 m thick overconsolidated clay layer has Cc = 0.35, Cr = 0.05 and e₀ = 1.05. At its mid-depth the effective vertical stress is 120 kPa and the preconsolidation pressure is 210 kPa. A new building adds 120 kPa of vertical stress at mid-depth. Find the primary consolidation settlement S in mm.
A clay layer 3 m thick has a coefficient of consolidation cv = 3 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 6.5 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 90% average consolidation the time factor is Tv = 0.848. How many years t does the layer take to reach 90% consolidation?