A Modified Oedometer Setup for Simultaneously Measuring Hydromechanical Stress-Strain Paths for Soils in the Unsaturated State

摘要

This article reports a modified setup for an automatic oedometer apparatus that was designed at the Universite de Sherbrooke, Quebec, Canada. The proposed setup can be used to simultaneously measure the superimposed volume change of a soil specimen caused by mechanical loading and suction imposition along with continuous measurement of water exchange. The combined use of air and water volume/pressure controllers allows the operator to use the axis translation technique to impose matric suction. The setup can also be used to carry out the conventional negative water column technique using a single burette or the water volume/ pressure controller to apply suction within the range of 0 kPa to 25 kPa under atmospheric air pressure conditions. A modified Tempe cell was designed to ensure the airtightness of the cell and enhance the freedom of the specimens to move vertically during one-dimensional loading and soil-water retention tests, which is particularly of interest for practical cases in which accurate vertical deformation measurement (as low as 0.02 %) is required. Details of the calibration and test procedures are described and discussed. The test results of reconstituted specimens of a fine sand mixture and Ascot Corner silt are also presented to demonstrate the key features of the modified apparatus.