How to set up swelling tests with GDSLAB's Oedometer logging module
This article explains how to configure a GDSLAB Oedometer logging stage to conduct swelling tests. It will cover
a) Determination of Swelling Pressure by constant volume,
b) Free swell and determination of Swelling Pressure by stepped loading
c) Free swell followed by oedometer test
This article will assume that the user has knowledge of the methodology for each of these types of tests.
Swelling Pressure at Constant Volume
Once an oedometer sample has been set up in GDSLAB create a new test stage using Oedometer Logging
In the test, type select the Swelling Test. No further settings are required. Once the test starts the height of the sample will be maintained constant and any load generated by sample swelling will be measured.
Free Swelling and determination of Swelling Pressure by stepped loading.
Once an oedometer sample has been set up in GDSLAB create a new test stage using Oedometer Logging
Set up a series of loading steps, starting at a small seating load, followed by a first load step and then subsequent load steps doubling the value of the previous step.
After the seating load is applied inundate the specimen. Wait until swell stops.
Once the swelling is over proceed to the loading increment and wait for the end of primary consolidation. Apply the next load steps in the same way until at the end of an increment the height of the sample is equal to or less than the original height.
Swell strain can be determined at the end of step 3. Swelling pressure can be determined by the graphical interpretation of void ratio vs vertical load plot
This is identical to the set up required for an oedometer test. The procedure is similar, with the main variation being the time the sample remains under sitting load. This method can be followed up by an oedometer test, by adding the oedometer loads to the last load used to finish the swell test.
Please note these steps are based on ASTM D4546 Standard Test Methods for One-Dimensional Swell or Collapse of Soils. They do not replace the methodology of the standard and may need to be adapted to different standards.
Free Swelling Followed by Oedometer Test.
Once an oedometer sample has been set up in GDSLAB create a new test stage using Oedometer Logging
Set up a series of loading steps, starting at a small seating load, followed by a first load step and then subsequent load steps doubling the value of the previous step.
After the seating load is applied inundate the specimen. Wait until swell stops.
Set up a new oedometer logging stage with the increments to be used for oedometer testing and then start the test.