DYNAMIC INSTABILITY OF COAL ROCK BURST IN SPATIOTEMPORAL MULTI-CRACK RVE MODEL

This study investigated the mechanism behind rock bursts induced by the initial release of high stress in deep coal mines. A dynamic instability criterion was established for coal rock bursts using a spatiotemporal multi-crack representative volume element (RVE) model. Firstly, Python-driven ABAQUS was used to develop Voronoi tessellation-generating (Voronoi_ABAQUS_Py) and cohesive element-inserting (Coh_3D_ABAQUS) programs. The initial stresses of 2, 4, and 6 MPa were then applied to the surfaces of cubic RVE models (with side lengths of 100 and 300 mm) to achieve a high strain energy state within the RVE. Finally, the strain energy was released by removing the RVE boundaries, allowing for the determination of rock burst strain, kinetic energy, and fracture energy. Considering the periodic conversion between kinetic and strain energies, the system energy attenuation rate was modeled using a Lyapunov equation, which facilitated the establishment of a dynamic instability criterion for coal rock bursts. The initial stress level showed a more pronounced impact on rock burst occurrence compared to the influence of crack density. At an initial stress level of 2 MPa, both cube RVE models retained their stability. When the stress level increased to 4 MPa, the 100 mm side-length model maintained dynamic stability, whereas under all other conditions, both cube RVE models underwent rock bursts. The results of this study provide a scientific approach for quantitatively predicting the dynamic disaster warning of rock bursts in deep coal mines.