Experimental Study on Mechanical Properties of Structured Clay under Different Unloading Rates and Unloading Stress Paths

Consolidated undrained triaxial shear tests were performed on undisturbed saturated structured clay at three unloading rates (0.1, 0.25, and 2.5 kPa/min) using a GDS system to determine the effects of different stress paths stress–strain relationship, pore pressure variation, failure strength characteristics Zhanjiang clay. Microstructural changes in observed during rates. Furthermore, obtained relationship indicates strain-softening under paths. Under same axial strain, larger rate caused deviatoric stress. conditions, higher confining pressure, greater peak smaller rate, development, variation pressure. Moreover, increased with an increase from 0.1 kPa/min. The change had effect passive tensile path than that compression path. microstructure changed after rates, exhibiting various degrees adjustment particle arrangement, contact relations, sizes, shapes.