Cyclic DSS tests for the evaluation of stress densification effects in liquefaction assessment

Abstract

To evaluate the stress correction factor for the Cyclic Resistance Ratio (“CRR”) under cyclic loading with principal stress rotation, 86 Cyclic Direct Simple Shear (CDSS) tests were performed on two sands, one from Ain Beniam, in Alger, Algeria, and another from Coimbra, Portugal. These sands have distinctive grain shapes and size distributions and were tested with various relative densities and under different initial effective confining stresses. The results of the tests performed with zero initial static shear stress – therefore with the static shear stress factor Kα equal to one – indicate that the values of confining stress level correction factor, Kσ, as currently recommended, seem to underestimate the cyclic resistance.