Soil Consolidation vs Settlement: What's the Difference?

Questions and Answers

All of the above

Elastic settlement

Plastic adjustment of soil fabrics

Primary consolidation settlement Signup and view all the answers

Theory of elasticity Signup and view all the answers

Sandy soils exhibit rapid drainage of pore water, whereas clay soils exhibit slow drainage Signup and view all the answers

Reduction in the volume of the soil mass Signup and view all the answers

Consolidation settlement is greater than elastic settlement Signup and view all the answers

To measure the excess hydrostatic pressure Signup and view all the answers

P/A Signup and view all the answers

Study Notes

Soil layers compress due to stress increase caused by construction of foundations or other loads, resulting in settlement.
Compression occurs due to:
- Deformation of soil particles
- Relocation of soil particles
- Expulsion of water or air from void spaces

Elastic settlement (or immediate settlement):
- Caused by elastic deformation of dry soil and moist/saturated soils without change in moisture content
- Calculations based on equations derived from elasticity theory
Primary consolidation settlement:
- Result of volume change in saturated cohesive soils due to expulsion of water from void spaces
Secondary consolidation settlement:
- Occurs in saturated cohesive soils due to plastic adjustment of soil fabrics
- Additional compression at constant effective stress

Total settlement (S T) = S c (primary consolidation settlement) + S s (secondary consolidation settlement) + S e (elastic settlement)

When a saturated soil layer is subjected to a stress increase, pore water pressure increases suddenly.
In sandy soils, drainage occurs immediately, resulting in settlement.
In compressible clay layers, elastic settlement occurs immediately, but consolidation occurs over a longer period due to slower drainage.

Can be understood by considering a simple model consisting of a cylinder with a spring at its center.
Load applied to the piston causes excess hydrostatic pressure, which can be measured by a pressure gauge.
The excess hydrostatic pressure can be calculated using equation (11.1).