Study on Discrete Element Simulation of Secondary Rock Failure Characteristics in Granular Media

The crushing degree of caved ore-rock is one of the key factors influencing the success of block caving mines. The secondary rock failure in granular media is a major link which influences the crushing degree of ore-rock. Rolling Resistance Linear (granules) and Flat-Joint Model (rocks) of discrete element software were used to establish a mathematical model of rocks in granular media. Failure characteristics in granular media of rocks with different mechanical properties were studied. The crushing rules of ore-rock were also analyzed. The study results show that, when the ratio of compressive strength and vertical stress of rocks (ky) is smaller than 1.37, the compressive strength plays a major role in rock failure. The generated cracks are mainly shear cracks. At this very moment, rocks can be broken into small-size granules. When ky is larger than 1.37, the tensile strength plays a major role in rock failure. Further, when the ratio of tensile strength and vertical stress (kl) is smaller than 0.32, generated cracks are mainly tensile cracks. At this very moment, rocks can be broken into big-size granules. When kl is larger than 0.32, rocks basically suffer no failure.