On the implementation of strain path testing

Studies of the stress strain behavior of soils under strain path controlled conditions are important in establishing the constitutive relationship of soils. However, such studies were difficult to conduct in the past because of the lack of an efficient strain path testing system and technique. In this paper, a technique for the implementation of triaxial strain path testing is presented. A strain path is controlled as the ratio of volumetric strain increment to the axial strain increment. A digital pressure/volumetric controller is used to control the volumetric change of the sample. The developed testing technique can be used to study the stress strain behavior under conditions which cannot be imposed by controlling the stress path. Several examples are given to illustrate the application of strain path testing in studying the constitutive behavior of soils.