Improvements to a Stress-Path Triaxial Cell
Stress-path triaxial cells are presently used all over the world. Accurate use of this type of apparatus allows an investigation into the mechanical behavior of soils with regard to a wide range of stress and strain. A correct evaluation of small-strain stiffness requires an accurate definition of the compliance curve of the apparatus and the possibility of performing tests in stress-controlled conditions. However, in the standard stress-path cell, compliance curves are often nonlinear and nonrepeatable. Moreover, in most standard stress-path apparatus, the pressure supply is limited to 1000 kPa, which makes it impossible to carry out stress-controlled tests at high confining pressures. The observation of these limitations prompted adjustments in the design of the cell, described in the present paper. With the revised design, it is possible to apply a deviatoric stress up to 1500 kPa under stress-controlled conditions with a cell pressure of 1000 kPa using a 1000-kPa pressure supply. The stiffness of the cell was also significantly increased, up to ten times the stiffness of the original design.