Undrained cyclic torsional shear behavior of saturated sand with initial static shear

Abstract

This paper summarizes the experimental results of a study conducted in order to investigate the effect of initial static shear on the undrained cyclic behavior of saturated sand under cyclic torsional shear loading up to single amplitude shear strain of about 50 (~o. Several hollow cylinder specimens at relative density of about 45 % were performed with varying the initial static shear and the subsequent cyclic hear stress levels. The observed failure behavior of specimens could be distinguished into liquefaction and residual deformation failures depending on the magnitude of' combined static and cyclic shear stress. In addition. it was found that the presence of static shear does not always lead to an increase in the resistances to liquefaction and strain accumulation. They could either increase or decrease with increasing the static shear depending 011 the magnitude of combined shear stress, the type of loading and the failure behavior.