Consolidation settlement worksheet with answers

Free printable Consolidation settlement worksheet: 6 problems from easy to exam level, with an answer key. Print it or save it as a PDF.

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1.Easy
Δσ = 75 kPasandclayCc​ = 0.5e0​ = 1.05σ′0​ = 110 kPa5 mwater table

A 5 m thick layer of normally consolidated clay (Cc = 0.5, e₀ = 1.05) has an effective vertical stress of 110 kPa at its mid-depth. A wide fill raises the vertical stress in 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.

H = 5 mCc = 0.5e0 = 1.05σ′0 = 110 kPaΔσ = 75 kPa
S = mm
2.Easy
Δσ = 125 kPasandγ = 17.5 kN/m³3.5 mclayγsat​ = 18.5 kN/m³Cc​ = 0.15, e0​ = 1.29 mwater tableX

A 9 m thick normally consolidated clay layer (γsat = 18.5 kN/m³, Cc = 0.15, e₀ = 1.2) 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 125 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 = 9 m, γsat = 18.5 kN/m³γw = 9.81 kN/m³Cc = 0.15e0 = 1.2Δσ = 125 kPa
S = mm
3.Medium
Δσ = 70 kPasandclayCc​ = 0.45, Cr​ = 0.02e0​ = 1.15σ′0​ = 120 kPaσ′p​ = 220 kPa5 mwater table

A 5 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 120 kPa and the preconsolidation pressure is 220 kPa. A new building adds 70 kPa of vertical stress at mid-depth. Find the primary consolidation settlement S in mm.

H = 5 mCc = 0.45Cr = 0.02e0 = 1.15σ′0 = 120 kPaσ′p = 220 kPaΔσ = 70 kPa
S = mm
4.Medium
Δσ = 15 kPasandclayCc​ = 0.5, Cr​ = 0.06e0​ = 0.9σ′0​ = 60 kPaσ′p​ = 110 kPa4.5 mwater table

A 4.5 m thick overconsolidated clay layer has Cc = 0.5, Cr = 0.06 and e₀ = 0.9. At its mid-depth the effective vertical stress is 60 kPa and the preconsolidation pressure is 110 kPa. A new building adds 15 kPa of vertical stress at mid-depth. Find the primary consolidation settlement S in mm.

H = 4.5 mCc = 0.5Cr = 0.06e0 = 0.9σ′0 = 60 kPaσ′p = 110 kPaΔσ = 15 kPa
S = mm
5.Hard
sandclayH = 9 m9 msandwater table

In a laboratory oedometer test, a clay specimen 25 mm thick, drained at the top and bottom, reaches 50% consolidation in 8 min. In the field the same clay forms a layer 9 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?

hlab = 25 mmtlab = 8 minH = 9 mfield: double drainage
t = days
6.Hard
sandclayH = 10 m10 msandwater table

In a laboratory oedometer test, a clay specimen 25 mm thick, drained at the top and bottom, reaches 50% consolidation in 6 min. In the field the same clay forms a layer 10 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?

hlab = 25 mmtlab = 6 minH = 10 mfield: double drainage
t = days

Answer key

  1. 1. S = 275.3 mm
  2. 2. S = 215.6 mm
  3. 3. S = 9.282 mm
  4. 4. S = 13.77 mm
  5. 5. t = 720 days
  6. 6. t = 666.7 days

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