Comportamiento de un material granular no tratado en ensayos triaxiales cíclicos con presión de confinamiento constante y variable

Abstract

In a pavement structure, passing wheel loads impose cyclic stresses consisting of vertical, horizontal and shear components. Studies of the behavior of unbound granular materials (UGM, used for base and sub-base layers) under cyclic loading are mostly performed using the axisymmetric triaxial test with constant confining pressure (CCP test) and a cyclic variation of the axial stress. However, in this type of test only the vertical component of the cyclic stress path is considered. The oscillation of the horizontal stress can be reproduced by an additional cyclic variation of the confining pressure (VCP test). CCP and VCP tests are sometimes assumed to deliver similar residual and resilient deformations as long as the average stress is the same in both types of tests. However, this assumption is based on limited test data in the literature. The present paper documents a more detailed comparative study with CCP and VCP tests. The results show that only for some special stress paths both types of test deliver similar permanent axial or volumetric deformation.