A novel cyclic loading–unloading contact model for rock using discrete element method

Abstract

In engineering disciplines such as tunnel construction, underground projects, oil and gas storage, and slope engineering, rocks frequently experience the effects of cyclic loading. Although existing contact models in commercial software can simulate rock materials, they demonstrate significant limitations in accurately capturing the mechanical behavior of materials under cyclic loading and unloading. In this research, a cyclic loading–unloading contact model, incorporating damage considerations, was developed specifically for rock materials. This developed discrete element method enhances the efficiency of model generation by improving internal algorithms and offers high editability. The numerical results were compared with experimental data and showed strong agreement across three different types of rock. The developed method and contact models effectively capture the plastic failure process of rock material under cyclic loading, with the resulting stress–strain curves displaying characteristic hysteresis loops. In comparison with traditional discrete element software using parallel bonding models, this program produces more accurate results, making it more suitable for simulating the cyclic loading–unloading behavior of rocks.