Behaviour of Rockfill Materials

For the present work two types of rockfill materials viz. riverbed (from seven project sites) and quarried (from three project sites) have been considered. These materials have been modeled to three smaller maximum particle sizes (dmax). Drained triaxial tests have been conducted on these modeled materials at four confining pressures. Breakage factors have been determined at the end of each triaxial test. For all the modeled rockfill materials, stress-strain-volume change responses have been plotted and phi-values have been determined. Various index properties viz. unconfined compressive strength (UCS) and uncompacted void content (UVC) of the rockfill materials have also been determined in the laboratory. The UCS represents the strength of the particles and UVC represents grading, size, shape, angularity and surface texture of the particles. The behaviour of the rockfill materials has been explained in terms of these index properties. A method has been proposed to relate the basic characteristics in terms of UCS and UVC of the rockfill materials with the shear strength parameter.