ISO/TS 17892-9:2004 covers the determination of stress-strain relationships and effective stress paths for a cylindrical, water-saturated specimen of undisturbed, remoulded or reconstituted soil when subjected to an isotropic or an anisotropic stress under undrained or drained conditions and thereafter sheared under undrained or drained conditions within the scope of the geotechnical investigations according to prEN 1997-1 and -2. The test methods provide data that are appropriate to present tables and plots of stress versus strain, and effective stress paths.
Special procedures such as:
a) Tests with lubricated ends;
b) tests with local measurement of strain or local measurement of pore pressure;
c) tests without rubber membranes;
d) extension tests;
e) shearing where cell pressure varies;
f) shearing at constant volume (no pore pressure change)
are not covered.
The conventional triaxial apparatus is not well suited for measurement of the initial moduli at very small strains. However, strains halfway up to failure are considered to be large enough to be measured in conventional triaxial cells.