For teachers: free to print, copy and use in class. Every new worksheet has new values and its own answer key. A link to ExamProblems on your course page is appreciated.
Name: ____________________ Date: ____________
1.Easy
A 10 m thick normally consolidated clay layer (γsat = 18 kN/m³, Cc = 0.35, e₀ = 1.35) lies below 5.5 m of sand (γ = 17 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 75 kPa. Treat the layer as one sublayer with the stresses at its mid-depth. Find the primary consolidation settlement S in mm.
sand: Hs = 5.5 m, γ = 17 kN/m³clay: H = 10 m, γsat = 18 kN/m³γw = 9.81 kN/m³Cc = 0.35e0 = 1.35Δσ = 75 kPa
S = mm
2.Easy
A 7 m thick normally consolidated clay layer (γsat = 18 kN/m³, Cc = 0.6, e₀ = 1.15) 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 105 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 = 7 m, γsat = 18 kN/m³γw = 9.81 kN/m³Cc = 0.6e0 = 1.15Δσ = 105 kPa
S = mm
3.Medium
A 7 m thick overconsolidated clay layer has Cc = 0.45, Cr = 0.02 and e₀ = 1.15. At its mid-depth the effective vertical stress is 80 kPa and the preconsolidation pressure is 150 kPa. A new building adds 10 kPa of vertical stress at mid-depth. Find the primary consolidation settlement S in mm.
A 4 m thick overconsolidated clay layer has Cc = 0.35, Cr = 0.03 and e₀ = 1.2. At its mid-depth the effective vertical stress is 55 kPa and the preconsolidation pressure is 95 kPa. A new building adds 160 kPa of vertical stress at mid-depth. Find the primary consolidation settlement S in mm.
A clay layer 4 m thick has a coefficient of consolidation cv = 5 m²/year. It lies between two sand layers, so water drains out at the top and the bottom. For 60% average consolidation the time factor is Tv = 0.287. How many years t does the layer take to reach 60% consolidation?
A clay layer 5.5 m thick has a coefficient of consolidation cv = 0.5 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?