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 = 115 kPasandclayCc​ = 0.6e0​ = 1.4σ′0​ = 70 kPa8 mwater table

An 8 m thick layer of normally consolidated clay (Cc = 0.6, e₀ = 1.4) has an effective vertical stress of 70 kPa at its mid-depth. A wide fill raises the vertical stress in the clay by 115 kPa. Treat the layer as one sublayer with the stresses at its mid-depth. Find the primary consolidation settlement S in mm.

H = 8 mCc = 0.6e0 = 1.4σ′0 = 70 kPaΔσ = 115 kPa
S = mm
2.Easy
Δσ = 25 kPasandclayCc​ = 0.35e0​ = 1.1σ′0​ = 75 kPa4 mwater table

A 4 m thick layer of normally consolidated clay (Cc = 0.35, e₀ = 1.1) has an effective vertical stress of 75 kPa at its mid-depth. A wide fill raises the vertical stress in the clay by 25 kPa. Treat the layer as one sublayer with the stresses at its mid-depth. Find the primary consolidation settlement S in mm.

H = 4 mCc = 0.35e0 = 1.1σ′0 = 75 kPaΔσ = 25 kPa
S = mm
3.Medium
Δσ = 190 kPasandclayCc​ = 0.4, Cr​ = 0.05e0​ = 1.05σ′0​ = 45 kPaOCR = 25.5 mwater table

A 5.5 m thick overconsolidated clay layer has Cc = 0.4, Cr = 0.05 and e₀ = 1.05. At its mid-depth the effective vertical stress is 45 kPa and the overconsolidation ratio is OCR = 2. A new building adds 190 kPa of vertical stress at mid-depth. Find the primary consolidation settlement S in mm.

H = 5.5 mCc = 0.4Cr = 0.05e0 = 1.05σ′0 = 45 kPaOCR = 2Δσ = 190 kPa
S = mm
4.Medium
Δσ = 190 kPasandclayCc​ = 0.25, Cr​ = 0.03e0​ = 0.9σ′0​ = 60 kPaσ′p​ = 150 kPa3 mwater table

A 3 m thick overconsolidated clay layer has Cc = 0.25, Cr = 0.03 and e₀ = 0.9. At its mid-depth the effective vertical stress is 60 kPa and the preconsolidation pressure is 150 kPa. A new building adds 190 kPa of vertical stress at mid-depth. Find the primary consolidation settlement S in mm.

H = 3 mCc = 0.25Cr = 0.03e0 = 0.9σ′0 = 60 kPaσ′p = 150 kPaΔσ = 190 kPa
S = mm
5.Hard
sandclayH = 6.5 mcv​ = 1.5 m²/year6.5 mimpervious rockwater table

A clay layer 6.5 m thick has a coefficient of consolidation cv = 1.5 m²/year. It lies on impervious rock, with sand above it, so water drains out only at the top. For 60% average consolidation the time factor is Tv = 0.287. How many years t does the layer take to reach 60% consolidation?

H = 6.5 mcv = 1.5 m²/yearU = 60%Tv = 0.287single drainage
t = years
6.Hard
sandclayH = 10 m10 msandwater table

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 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 = 19 mmtlab = 10 minH = 10 mfield: double drainage
t = days

Answer key

  1. 1. S = 844.1 mm
  2. 2. S = 83.29 mm
  3. 3. S = 487.7 mm
  4. 4. S = 106.4 mm
  5. 5. t = 8.084 years
  6. 6. t = 1924 days

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