ABSTRACT

The UWA DSS is based on the UC Berkeley DSS, in that it tests a cylindrical specimen enclosed in a latex membrane within a pressurised cell, just like a triaxial specimen. In contrast, the NGI-type DSS uses wire winding around the specimen to provide the lateral confinement. With independent control of the vertical and horizontal stresses, it is possible in theory to apply any desired initial consolidation stresses to the specimen in the UWA DSS, though there are limitations to this, as will be explained later. One of the major advantages of the UWA (and Berkeley) apparatus is the ability to apply an elevated back pressure (ensuring full saturation), and the consequent ability to measure the pore pressure changes accurately in an undrained test. Hence it is possible to determine the effective stresses as well as the total stresses in an undrained test.