A new suction and temperature controlled triaxial apparatus

In this paper a new hydraulically controlled triaxial apparatus, designed specifically for testing unsaturated soils under nonisothermal conditions, is described. Novel features of the equipment are the use of a laser-based system to measure radial deformation throughout the specimen height, the simultaneous application to both ends of the sample of the air and water pressures required for matric suction control and the incorporation of an external heating system to perform non-isothermal paths. The paper also contains selected results of isotropic suction controlled wetting paths on clay specimens under isothermal conditions, showing the time evolution of axial and radial strains as well as the progressive development of the lateral profiles of the sample. Some results of non-isothermal paths under constant matric suction are also presented.