Skip to main content

Residual and transported soils

Short answer

Residual soils remain over parent rock after weathering, are angular and unsorted; transported soils are moved by water, wind, ice or gravity, are rounded and layered. Solutions to soil problems include deep foundations, compaction, drainage, stabilization, and retaining walls.

Differentiate between residual and transported soils. What would be a solution of different soil engineering problems?

Residual soils are formed by weathering of rock and remain at the place of formation. Transported soils are weathered particles carried by an agent and deposited away from the parent rock.

BasisResidual soilTransported soil
LocationAt the parent rockFar from the parent rock
AgentNoneWater, wind, ice, gravity
ParticlesAngular, unsortedRounded and sorted by size
DepthVariable, grades into rock belowOften thick and layered
Grain sizeWide mixture; fine at top, coarse at bottomFairly uniform in each layer
ExamplesLaterite, black cotton soilAlluvial, loess, glacial till, colluvium
StrengthDepends on weathering depth; weathered rock can be strongOften loose and compressible

Solutions to soil problems

  • Settlement: compaction, preloading, drains, or deep foundations.
  • Low strength: stabilisation, soil replacement, reinforcement with geosynthetics.
  • Slope failure: drainage, retaining structures, slope flattening.
  • Seepage: cut-off, filters and sheet piles.
  • Expansive soil: lime treatment, replacement, and deep foundations.

✓ Answer checked by Claude Opus 5.5 (high effort)

Related questions

All Soil Mechanics chapter 1 questions →