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Name: ____________________ Date: ____________
1.Easy
An 8 m thick normally consolidated clay layer (γsat = 18.5 kN/m³, Cc = 0.45, e₀ = 1.35) 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 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 = 18 kN/m³clay: H = 8 m, γsat = 18.5 kN/m³γw = 9.81 kN/m³Cc = 0.45e0 = 1.35Δσ = 115 kPa
S = mm
2.Easy
A 5 m thick layer of normally consolidated clay (Cc = 0.5, e₀ = 1.3) has an effective vertical stress of 55 kPa at its mid-depth. A wide fill raises the vertical stress in the clay by 35 kPa. Treat the layer as one sublayer with the stresses at its mid-depth. Find the primary consolidation settlement S in mm.
H = 5 mCc = 0.5e0 = 1.3σ′0 = 55 kPaΔσ = 35 kPa
S = mm
3.Medium
A 6 m thick overconsolidated clay layer has Cc = 0.35, Cr = 0.02 and e₀ = 0.65. At its mid-depth the effective vertical stress is 65 kPa and the overconsolidation ratio is OCR = 1.5. A new building adds 70 kPa of vertical stress at mid-depth. Find the primary consolidation settlement S in mm.
A 3 m thick overconsolidated clay layer has Cc = 0.3, Cr = 0.04 and e₀ = 1.1. At its mid-depth the effective vertical stress is 60 kPa and the overconsolidation ratio is OCR = 2. A new building adds 140 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 = 4 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?
A clay layer 3.5 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 90% average consolidation the time factor is Tv = 0.848. How many years t does the layer take to reach 90% consolidation?