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 5 m thick normally consolidated clay layer (γsat = 19 kN/m³, Cc = 0.45, e₀ = 0.85) lies below 2.5 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 120 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 = 17.5 kN/m³clay: H = 5 m, γsat = 19 kN/m³γw = 9.81 kN/m³Cc = 0.45e0 = 0.85Δσ = 120 kPa
S = mm
2.Easy
A 7 m thick normally consolidated clay layer (γsat = 18 kN/m³, Cc = 0.35, e₀ = 0.6) lies below 5.5 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 45 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 = 18.5 kN/m³clay: H = 7 m, γsat = 18 kN/m³γw = 9.81 kN/m³Cc = 0.35e0 = 0.6Δσ = 45 kPa
S = mm
3.Medium
A 6 m thick overconsolidated clay layer has Cc = 0.35, Cr = 0.02 and e₀ = 1.2. At its mid-depth the effective vertical stress is 60 kPa and the preconsolidation pressure is 180 kPa. A new building adds 35 kPa of vertical stress at mid-depth. Find the primary consolidation settlement S in mm.
An 8 m thick overconsolidated clay layer has Cc = 0.5, Cr = 0.05 and e₀ = 1.2. At its mid-depth the effective vertical stress is 55 kPa and the overconsolidation ratio is OCR = 3. A new building adds 180 kPa of vertical stress at mid-depth. Find the primary consolidation settlement S in mm.
In a laboratory oedometer test, a clay specimen 19 mm thick, drained at the top and bottom, reaches 50% consolidation in 10 min. In the field the same clay forms a layer 6 m thick. It lies between two sand layers, so water drains out at the top and the bottom. How many days t does the field layer take to reach 50% consolidation?
A clay layer 9 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?