Null-type axis-translation technique: Is it applicable to soils with low saturation?

The applicability of the axis-translation technique for controlling and measuring the matric suction of the soils with occluded air phase has been extensively studied. However, there is little known about whether this technique can be used for matric suction measurements of the soils with occluded water phase or with low saturations. In this study, granular soils that have low matric suctions and low saturations were tested using the null-type axis-translation technique. In order to compare the results obtained by the axis-translation technique, the suctions of the samples were also measured using standard tensiometers. It is found that matric suction measurements took substantially longer time for the samples with lower water contents (about 6.5% and less). This is attributed to the discontinuous water phase within those samples. In addition to that, matric suction values measured using the null method were close to the values measured with a tensiometer. This is a promising result on the applicability of the null method to measure the matric suction of the soils with low saturation. However, the method seems to be very time consuming and therefore, not very practical. © 2012 IEEE.