Soil behavior under low- and high-cycle loading—Element tests vs. constitutive models

Abstract

The first part of the paper deals with high-cycle loading and presents a parametric study with numerous drained cyclic tests with a large number of cycles (N≥104). The dependence of the strain accumulation rate on initial relative density, amplitude, average stress and cyclic preloading is addressed. These test series form the basis of the calibration of a high-cycle accumulation (HCA) model, which is briefly explained. Furthermore, the influences of the grain size distribution curve, particle shape and the sample preparation method on the cumulative strains are discussed. In further test series the effects of multiple changes of the direction of the cycles, of frequently changing amplitudes, and of changes of the average stress between bundles of cycles were investigated. The second part of the paper is dedicated to low-cycle loading. A data base with a large number of undrained cyclic triaxial tests performed on a fine sand is presented. The test conditions comprise stress or strain-controlled cycles, performed from isotropic or anisotropic initial stresses and involving different densities and amplitudes. The predictions of three sophisticated constitutive models for sand, namely hypoplasticity with intergranular strain, ISA and Sanisand, are tested against the experimental data. Finally, a second data base concerning a large number of cyclic tests on kaolin is briefly introduced.