SOIL SETTLEMENT: PART 5 - SECONDARY CONSOLIDATION

THEORY

After the soil completes primary consolidation, the settlement continues by changing of physical structures of the soil fabric. This is so-called Secondary Consolidation or Creep.

The method to predict creep is not reliable and specific to soil types. A method suggested in Das (2002) can be used to compute secondary consolidation from t1 --> t2 after the end of the primary consolidation.

where

The general magnitude of

for various natural deposits are as follows:

OC Clays < 0.001

NC Clays are between 0.005 and 0.03

Organic Soil is 0.04 or more (***)

CONCLUSIONS

As described in Teng (1962), secondary consolidation for most natural soil deposits is relatively small compared to primary consolidation. However, the magnitude of secondary consolidation is large for organic soils and most plastic clays.

EXAMPLE

(Coming soon)

REFERENCES

BM Das, Principles of Geotechnical Engineering, 5th ed., Brook/Cole Thompson, 2002

WC Teng, Foundation Design, Prentice-Hall, 1962