Experimental Investigation on Loading-Relaxation Behaviors of Shear-Zone Soil

Abstract

This paper presents an experimental investigation on the loading-relaxation behaviors of reconstituted shear-zone soils through drained triaxial tests. A multistage loading-relaxation approach is adopted to perform this test. The test aims to study two main issues: the influence of relaxation on the mechanical response during reloading; and the influence of strain rates, loading increments, and the relaxation time on the relaxation characteristics. The test results indicate that the stress-relaxation behavior of shear-zone soil is dependent on the stress and strain levels. The loading patterns prior to the stress-relaxation process affect mainly the viscoelastic behavior of the soil and subsequently influence the initial relaxation behavior. Moreover, a reloading after a stress-relaxation process gives rise to a higher deviatoric stress owing to the viscoplastic hardening. It is further shown that the loading-relaxation behaviors can be interpreted by the viscoplastic theory.