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Situations demanding pile foundation

Short answer

Piles are required when surface soils are weak or compressible, for heavy loads from tall structures, to control settlement or uplift, in high water tables, scour-prone or expansive soil sites, and to avoid disturbing adjacent buildings or excavation.

Enumerate the situations demanding the use of piles as foundations.

Pile foundations are used when shallow foundations are not suitable or economical. The situations are:

  1. Weak surface soil: A thick layer of soft clay, loose sand, peat or fill above, with hard stratum or rock at a lower depth; piles carry load to the firm layer (end-bearing piles).
  2. Heavy loads: Tall buildings, bridges, towers and industrial structures whose loads shallow footings cannot carry.
  3. Large settlement expected: Compressible soils, where settlement of shallow footings is excessive.
  4. High water table or submerged site: Excavation of shallow foundation is hard (river, marine, bridge piers).
  5. Uplift or overturning loads: Transmission towers, chimneys, basement under water pressure; piles resist tension.
  6. Lateral loads: Wind, earthquake, or water pressure on retaining walls, jetties, and docks (raked piles).
  7. Scour risk: River bed erosion around foundations of bridges.
  8. Expansive soils (black cotton): Piles go below the zone of seasonal change.
  9. Liquefaction-prone soil in earthquake areas.
  10. Adjacent structures or very deep excavations, where shallow footings would disturb nearby buildings.
  11. Compaction of loose sand (compaction piles).

✓ Answer checked by Claude Opus 5.5 (high effort)

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