Development of a New Hollow Cylinder Triaxial Apparatus for the Study of Expansion Tests in Clay

This paper presents the use of a new, automated, Hollow Cylinder Triaxial cell (HCTA) for the study of expansion tests in saturated clay. The hollow cylinder cell was developed by modifying a hydraulic triaxial cell, and was adapted to perform cylindrical cavity expansion tests in annular soil specimens, with measurement of excess pore water pressures generated at various radial distances. The apparatus allows one to perform drained and undrained expansion tests, under plane strain or constant axial stress, with the expansion process being either stress-controlled or strain-controlled. The equipment, testing procedures, and analysis of typical undrained expansion tests are discussed.