Laboratory tests on undisturbed and remolded Shanghai clay were conducted with a novel mixed boundary true triaxial apparatus. The strength and deformation behaviors of the structured soft clay at different Lode angles were carefully investigated. The relationship between the shear stress ratio and the dilatancy ratio of the clay in three different stress spaces, that is p-q space, transformed stress (TS) space, and tij modified stress space, is discussed in detail. In particular, the influences of the stress path and the structure of nondisturbed clay on the strength, deformation, and failure criterion of Shanghai clay were quantitatively evaluated. The shear strength and dilatancy of undisturbed/remolded clay decreases with the increase of the Lode angle. It is also found that the shear strength and dilatancy of the undisturbed clay are larger than those of the remolded clay, while the influence of the structure on the dilatancy decreases with an increase in the Lode angle. In the pi-plane, the maximum strength of Shanghai clay under different stress paths generally obeys the spatial mobilized plane failure criterion. The coincidence of the stress-dilatancy relationship given by the TS and tij stress spaces with the test results is much better than that given by p-q stress space. Furthermore, the linearity of the plastic potential curves of the undisturbed/remolded clay is more evident in tij stress space.

来源平台：CANADIAN GEOTECHNICAL JOURNAL