Development of an Alternative Total Volume Change Measuring System for Samples in Unsaturated Conditions in Triaxial Tests

摘要

In the evaluation of unsaturated soil behavior, the measure of total volume change is more difficult and complicated than in a saturated soil. In this context, this paper presents a new system to estimate the total volume change of the soil in unsaturated conditions in triaxial tests. To do so, it was developed a double wall triaxial cell, where inner cell was connected to an airtight container subjected to the same cell pressure and positioned on a high precision analytical scale. The measurement of the total volume change is performed by the ratio of the mass of water entering or leaving the airtight container. After calibration, the system was tested. When comparing the volume change of the specimen recorded by the conventional method and the variation of volume obtained through the developed system, a maximum difference of 0.01 cm3 is obtained, which equals to 0.01% of the specimen volume.