Peak and critical-state shear strength of mine waste rock

Proper characterization of the peak and critical-state shear strength parameters required for geotechnical analyses involving geomaterials with large particle sizes such as mine waste rock, rockfill and coarse aggregates is challenging. This paper summarizes the results of previous studies related to large-scale triaxial testing and analysis of such geomaterials. Relevant experimental issues such as appropriate sample-size ratio selection, membrane penetration and particle breakage are discussed. The main steps required to perform a rigorous analysis of triaxial test results are outlined that avoid usual misinterpretations associated with conventional analysis of triaxial tests.A methodology integrating a robust experimental protocol with a rigorous theoretical framework is presented. The proposed methodology can be used to predict the shear strength of mine waste rock, rockfill, coarse aggregates and other types of uncemented geomaterials with large particle sizes under combinations of density and mean effective stress that are relevant to most geotechnical and mining applications.