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 = 125 kPasandγ = 18 kN/m³3 mclayγsat​ = 18.5 kN/m³Cc​ = 0.4, e0​ = 1.33 mwater tableX

A 3 m thick normally consolidated clay layer (γsat = 18.5 kN/m³, Cc = 0.4, e₀ = 1.3) lies below 3 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 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 m, γ = 18 kN/m³clay: H = 3 m, γsat = 18.5 kN/m³γw = 9.81 kN/m³Cc = 0.4e0 = 1.3Δσ = 125 kPa
S = mm
2.Easy
Δσ = 150 kPasandγ = 19 kN/m³4.5 mclayγsat​ = 18 kN/m³Cc​ = 0.25, e0​ = 0.659 mwater tableX

A 9 m thick normally consolidated clay layer (γsat = 18 kN/m³, Cc = 0.25, e₀ = 0.65) lies below 4.5 m of sand (γ = 19 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 150 kPa. Treat the layer as one sublayer with the stresses at its mid-depth. Find the primary consolidation settlement S in mm.

sand: Hs = 4.5 m, γ = 19 kN/m³clay: H = 9 m, γsat = 18 kN/m³γw = 9.81 kN/m³Cc = 0.25e0 = 0.65Δσ = 150 kPa
S = mm
3.Medium
Δσ = 140 kPasandclayCc​ = 0.25, Cr​ = 0.05e0​ = 0.75σ′0​ = 60 kPaOCR = 35 mwater table

A 5 m thick overconsolidated clay layer has Cc = 0.25, Cr = 0.05 and e₀ = 0.75. At its mid-depth the effective vertical stress is 60 kPa and the overconsolidation ratio is OCR = 3. A new building adds 140 kPa of vertical stress at mid-depth. Find the primary consolidation settlement S in mm.

H = 5 mCc = 0.25Cr = 0.05e0 = 0.75σ′0 = 60 kPaOCR = 3Δσ = 140 kPa
S = mm
4.Medium
Δσ = 70 kPasandclayCc​ = 0.35, Cr​ = 0.06e0​ = 0.85σ′0​ = 95 kPaOCR = 2.55.5 mwater table

A 5.5 m thick overconsolidated clay layer has Cc = 0.35, Cr = 0.06 and e₀ = 0.85. At its mid-depth the effective vertical stress is 95 kPa and the overconsolidation ratio is OCR = 2.5. A new building adds 70 kPa of vertical stress at mid-depth. Find the primary consolidation settlement S in mm.

H = 5.5 mCc = 0.35Cr = 0.06e0 = 0.85σ′0 = 95 kPaOCR = 2.5Δσ = 70 kPa
S = mm
5.Hard
sandclayH = 4.5 m4.5 msandwater table

In a laboratory oedometer test, a clay specimen 25 mm thick, drained at the top and bottom, reaches 50% consolidation in 5 min. In the field the same clay forms a layer 4.5 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 = 5 minH = 4.5 mfield: double drainage
t = days
6.Hard
sandclayH = 6.5 m6.5 mimpervious rockwater table

In a laboratory oedometer test, a clay specimen 20 mm thick, drained at the top and bottom, reaches 50% consolidation in 6 min. In the field the same clay forms a layer 6.5 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 = 6 minH = 6.5 mfield: single drainage
t = days

Answer key

  1. 1. S = 238.5 mm
  2. 2. S = 473.9 mm
  3. 3. S = 100.8 mm
  4. 4. S = 42.77 mm
  5. 5. t = 112.5 days
  6. 6. t = 1760 days

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