Abstract
This paper describes the design of equipment for examining the behavior of unsaturated granular soils at low stress levels. The one-dimensional compressibility is examined in a 254-mm-diameter compression cell whose unique features include the measurement and control of low-level stresses using load cells incorporated in the loading platen and the ability to determine suctions at the base and top of the specimen. Stiffness and strength behavior is examined in a new double wall triaxial cell that allows accurate determination of the volume change of the 150-mm-diameter unsaturated specimen. Facilities are incorporated in the cell for monitoring axial and radial strains on the central portion of the specimen. A technique for preparing compacted specimens without damaging the brittle high-entry ceramics in the base plates of the cells is described. The performance of the new equipment is discussed, and results of repeatability tests are reported.
