Technical NoteEffects of grading and particle characteristics on small strain properties of granular materials

A series of drained triaxial compression tests was conducted in order to evaluate the effects of grading and particle characteristics on the small strain stiffness of a wide variety of granular materials. To evaluate the quasi-elastic deformation property at small strain levels around 0.001% by static measurement, many small vertical cycles were applied at two isotropic stress states. The effects of maximum and mean particle diameters, fines content, coefficient of uniformity, and degree of particle angularity on the quasi-elastic vertical Young׳s moduli, Evs, by the static measurement were investigated. Within the limited range of grading and particle characteristics tested in the present study, the results showed that: (1) the Evs values were generally independent of maximum and mean particle diameters; (2) the Evs values seemed to decrease with increasing coefficient of uniformity; (3) the effects of fines content and particle angularity on the Evs values were not clear; and (4) the effects of the effective confining pressure on the above-mentioned three trends were insignificant.