Effect of principal stress rotation on deformation behavior of dense sand-clay mixtures

This paper investigated the deformation behaviour of K-consolidated sand-clay mixtures through cyclic triaxial (CT) and hollow cylinder (CHC) tests. The sand-clay mixtures contained 0%, 5%, 10% and 20% clay by weight and were prepared at a relative density of 75%. Clay inclusion caused an increase in the permanent axial strain of mixtures (0.075% to 5% in CT and 0.186% to 5% in CHC), while a relatively insignificant increase in permanent axial strain was observed in the CT specimens containing 5% and 10% clay (0.075% to 1.299%). However, all CHC specimens with clay failed (epsilon(z) >= 5%). It was also observed that shear strain development of sand is significantly influenced by clay inclusion (0.096-2.241%) in CHC tests. Test results clearly show that the effect of a principal stress rotation should be taken into account to better estimate the deformation behaviour of sand-clay mixtures under repetitive traffic loads.