Time dependence of swelling in oedometer tests on expansive soil

The manner in which oedometer tests are performed will influence the test results greatly. One important factor is the time allowed for each phase of the test to be completed. Not uncommonly, after inundation of the sample, the next load, and all subsequent increments of loading, are applied after a period of 24 hours. This may not be adequate for the heave to be fully developed. The results of oedometer tests are presented in which the times required for the various phases of the test to be completed were measured. After adding water, there is a period of time before swelling begins. This time period is influenced by the inundation stress. The amount of time over which swelling occurred varied significantly with applied stress. It was also shown that the manner by which the specimens in the oedometer were wetted influenced the time over which swelling occurred. When the specimens were wetted from the bottom of the sample with the top left open, swelling occurred for a longer period of time, and in greater amount, than when the entire sample was submerged.