Induced anisotropy under three-dimensional stress conditions is one of the important factors in the accurate prediction of ground deformation and should be a primary consideration not only in the laboratory but also in the field. To achieve this objective, torsional shear tests for saturated cohesive soils with induced anisotropy were performed. Induced anisotropy was generated by the shear history under constant p' (effective mean principal stress), α (direction of major principal stress) and b (intermediate principal stress coefficient) conditions in this study. The parameters α and b were also set up during the shear history process, and the drained torsional shear tests were carried out under constant p', α and b conditions using these specimens. The behaviour of soils during this process was examined in detail.

The elastic boundary induced by the shear history was represented in three dimensional space. Furthermore, the uniqueness of this elastic boundary was examined by changing the stress level and the material of the specimen. In conclusion, the uniqueness of the elastic boundary induced by the pure shear history (consant p') on saturated cohesive soils was verified via these experimental results. The application of the elastic boundary in a wide range of stress level and material was thus shown.