Аннотация:The study and description of the patterns of shear resistance and deformation of rockfill materials, as well as the development of a methodology for determining their parameters using specialized equipment are an urgent scientific and practical task. The article demonstrates a method for studying the mechanical properties of rockfill materials in a true triaxial compression device. During loading with different path lying in the deviatory plane, points belonging to the yield surface were obtained. By means of the developed technique, the meridian and deviatory cross-section of the yield surface in the space of the main stresses are determined.