Undrained cyclic shear strength and residual shear strain of saturated sand by cyclic triaxial tests

The undrained cyclic triaxial behaviour of saturated sand was studied using isotropically and anisotropically consolidated specimens. The strength and deformation under various combinations of initial static and cyclic shear stresses were considered. The cyclic strength was first discussed, and the residual shear strain was then investigated related with effective stress ratio at the end of each stress cycle. Further, a unique relationship was found between a relative effective stress ratio η* and the cyclic strength ratio R/R_f, where η* is the relative position between the initial and failure effective stress ratios, and R/R_f the ratio of the amplitude of cyclic shear stress to cyclic shear strength in arbitrary number of cycles. An empirical model was finally proposed for evaluating the development of pore pressure and residual shear strain of saturated sand subjected to various initial static and subsequent cyclic shear stresses.