Stabilising volume change characteristics of expansive soils using electrokinetics : A laboratory based investigation

The objective of this project was to investigate the potential of electrokinetic treatment techniques to stabilise volume change characteristics of expansive soils. The investigations were carried out in the laboratory using locally collected expansive soils from three locations in central Victoria, Australia. A layer of soil was placed in glass tanks (900 mm x 350mm plan area) and compacted to a known density and water content typical of field conditions. Using electrodes inserted into the soil, a direct current was passed across the soil under different voltage gradients of 0.5, 1.0 and 2.0 V/cm for periods of 3, 5, 7, 10 and 14 days. After electrokinetic processing, soil were tested for volume change properties using soil reactivity indicators such as consistency limits, linear shrinkage, free swell index and shrink-swell index. The test results show that with electrokinetic treatments, the volume change potentials of the experimental soils reduced to a greater or lesser degree depending on the magnitude of the voltage gradient and processing time. Under certain voltage gradients and treatment durations, some experimental soils transformed from extremely reactive status to a slightly or almost non-reactive status. The experimental results suggest the potential of developing electrokinetic treatment technique to stabilise volume change properties of expansive soils effectively and efficiently