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Causes of foundation failure

Short answer

Foundation failure stems from differential settlement due to uneven soil bearing, weak ground causing shear failure, consolidation of compressible soil, lateral soil movement, water table changes, expansive soil behaviour, tree root moisture extraction, poor construction, adjacent excavations, chemical attack, seismic activity, frost, and underground voids.

Describe the causes of foundation failure (list the common foundation failures).

Foundation failure means the foundation can no longer support the structure safely, because of shear failure of the soil or excessive (differential) settlement. Common causes are:

  1. Unequal bearing capacity or non-uniform soil under different parts of the foundation, giving differential settlement.
  2. Weak or overloaded soil: Bearing capacity less than the pressure applied; shear failure.
  3. Settlement due to consolidation of clay or other compressible soil, and loss of soil by erosion.
  4. Lateral movement of soil (sliding of sloping ground, squeezing of soft soil out from under the footing).
  5. Variation of water table and flooding; withdrawal of ground water.
  6. Seasonal swelling and shrinkage of expansive soils such as black cotton soil.
  7. Tree roots drawing moisture from the soil near the foundation, causing shrinkage.
  8. Poor design and construction: Inadequate depth, size, or concrete quality; construction on filled ground, poor compaction; unequal loading.
  9. Adjacent excavations or construction removing lateral support.
  10. Chemical attack (sulphates) and corrosion of the foundation.
  11. Earthquake and vibrations causing liquefaction or compaction.
  12. Frost action in cold areas.
  13. Underground voids (mines, caves, leaking pipes).

✓ Answer checked by Claude Opus 5.5 (high effort)

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