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 = 55 kPasandclayCc​ = 0.45e0​ = 0.75σ′0​ = 75 kPa8.5 mwater table

An 8.5 m thick layer of normally consolidated clay (Cc = 0.45, e₀ = 0.75) has an effective vertical stress of 75 kPa at its mid-depth. A wide fill raises the vertical stress in the clay by 55 kPa. Treat the layer as one sublayer with the stresses at its mid-depth. Find the primary consolidation settlement S in mm.

H = 8.5 mCc = 0.45e0 = 0.75σ′0 = 75 kPaΔσ = 55 kPa
S = mm
2.Easy
Δσ = 120 kPasandclayCc​ = 0.2e0​ = 1.05σ′0​ = 45 kPa5 mwater table

A 5 m thick layer of normally consolidated clay (Cc = 0.2, e₀ = 1.05) has an effective vertical stress of 45 kPa at its mid-depth. A wide fill raises the vertical stress in 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.

H = 5 mCc = 0.2e0 = 1.05σ′0 = 45 kPaΔσ = 120 kPa
S = mm
3.Medium
Δσ = 180 kPasandclayCc​ = 0.2, Cr​ = 0.03e0​ = 0.65σ′0​ = 60 kPaσ′p​ = 150 kPa4 mwater table

A 4 m thick overconsolidated clay layer has Cc = 0.2, Cr = 0.03 and e₀ = 0.65. At its mid-depth the effective vertical stress is 60 kPa and the preconsolidation pressure is 150 kPa. A new building adds 180 kPa of vertical stress at mid-depth. Find the primary consolidation settlement S in mm.

H = 4 mCc = 0.2Cr = 0.03e0 = 0.65σ′0 = 60 kPaσ′p = 150 kPaΔσ = 180 kPa
S = mm
4.Medium
Δσ = 25 kPasandclayCc​ = 0.2, Cr​ = 0.06e0​ = 1.05σ′0​ = 115 kPaσ′p​ = 145 kPa8 mwater table

An 8 m thick overconsolidated clay layer has Cc = 0.2, Cr = 0.06 and e₀ = 1.05. At its mid-depth the effective vertical stress is 115 kPa and the preconsolidation pressure is 145 kPa. A new building adds 25 kPa of vertical stress at mid-depth. Find the primary consolidation settlement S in mm.

H = 8 mCc = 0.2Cr = 0.06e0 = 1.05σ′0 = 115 kPaσ′p = 145 kPaΔσ = 25 kPa
S = mm
5.Hard
sandclayH = 7 m7 mimpervious rockwater table

In a laboratory oedometer test, a clay specimen 20 mm thick, drained at the top and bottom, reaches 50% consolidation in 5 min. In the field the same clay forms a layer 7 m thick. It lies on impervious rock, with sand above it, so water drains out only at the top. How many days t does the field layer take to reach 50% consolidation?

hlab = 20 mmtlab = 5 minH = 7 mfield: single drainage
t = days
6.Hard
sandclayH = 5 mcv​ = 1.2 m²/year5 mimpervious rockwater table

A clay layer 5 m thick has a coefficient of consolidation cv = 1.2 m²/year. It lies on impervious rock, with sand above it, so water drains out only at the top. For 80% average consolidation the time factor is Tv = 0.567. How many years t does the layer take to reach 80% consolidation?

H = 5 mcv = 1.2 m²/yearU = 80%Tv = 0.567single drainage
t = years

Answer key

  1. 1. S = 522.1 mm
  2. 2. S = 275.3 mm
  3. 3. S = 127.9 mm
  4. 4. S = 20 mm
  5. 5. t = 1701 days
  6. 6. t = 11.81 years

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