An overview on elementary mechanical behaviors, constitutive modeling and failure criterion of soils

The elementary mechanical behaviors, constitutive modeling and failure criterion of soils from an important theoretical basis for the discipline of soil mechanics and geotechnical engineering. This paper focuses on the mechanical behaviors of saturated clay, sand and rockfill materials (coarse granular aggregates) and a review for the recent development of constitutive modeling and failure criterion of these three types of the soils is presented. Some typical mechanical behaviors of saturated clay including compression behavior, shear behavior-critical state and dilatancy, behaviour of natural clay with loss of structure, influence of second principal stress, induced anisotropy and effect of principal stress rotation, undrained shear strength, time-dependency, and micromechanics-based analytical modeling are introduced first. Then, several important issues regarding the mechanical properties of sand are discussed, which involve the critical state framework and state-dependent dilatancy, anisotripic sand behaviour, strain localization and shear bending. Finally the researches on the influences of particle crushing on the mechanical behavior of rockfill materials (coarse granular aggregates) are particularly concerned. Attention is given to descriptive methods for particle crushing, the impact of breakage on the dilatancy, critical state line and stress-strain relationship, and macro-micro mechanical modeling.