Abstract：The test results of two rockfill samples are obtained with large-scale testing equipment. Based on these results，some useful conclusions are drawn from the analysis of deformation in each direction and shear strength properties of the rockfills. Thus，the exponent formulations of the relationship between deviator stress and axial strain or lateral strain and axial strain are proposed，respectively. Besides，the failure envelopes of rockfills in the coordinate plane of octahedral shear stress and octahedral normal stress also can be described by the exponent formulation. At the same time，the inherent mechanism of experimental phenomena is discussed. The relations among dilation，particle breakage and rearrangement are analysed，and the concept of reciprocal transformation of elastic dilatancy and plastic dilatancy is put forward.
