## 2 A Novel 3D Discrete Element Numerical Analysis Method for Rockburst
### Rockburst Simulation Analysis Method Based on the Bonded Block Model and Energy Index  
The Bonded block model (BBM) is a 3D block model developed based on 3 DEC [25]. The numerical model is established by Rhino, and the surface mesh and volume mesh are divided by the Gridle plug-in. In the Gridle plug-in, the Gint command can automatically generate interactive mesh, while the Gsurf command is used to re-divide the selected surface mesh into the required block size and type. The surface mesh is further used as input data to the Gvol command for volume subdivision, which can fill tetrahedral blocks to generate a file format for 3 DEC. Through the \"Rhino-Griddle-3 DEC\" numerical modeling method, the BBM complete model file is output and directly imported into numerical code. Then, the gen edge command can be used for secondary meshing in 3 DEC. The above meshing principle can effectively adjust the quality and size of the mesh, and an appropriate meshing can balance the calculation accuracy and calculation efficiency. With the help of the BBM, the connection between the block and micro crack in the model can be well simulated, and the initiation, inoculation, and propagation process of the simulated crack within the rock mass can be realized. BBM block elements can be characterized by polyhedral geometry, such as Voronoi and tetrahedral elements. Each block is interlocking with its surrounding blocks and bonded together through contact points. The contact represents a network of non-perforating and open cracks, and the block itself represents a complete block. The interaction between blocks is transmitted through contact points, which can characterize both the macroscopic mechanical behavior of rock mass and the microscopic characteristics of fracture propagation between blocks accurately. Many scholars have conducted relevant numerical research based on BBM [26; 27].  
To accurately depict the characteristics of the fracture information and strain-structural plane slip rockburst catastrophe, a novel rockburst numerical analysis method is proposed using the BBM and rockburst index \(C_{rs}\). Affected by factors such as computational efficiency, the block is composed of tetrahedral units, and the technical links of the method are shown in Figure 1. The method solves the shortcomings of traditional direct modeling or FISH modeling, speeds up modeling, and improves computational accuracy. It can not only  
\begin{table}
\begin{tabular}{c c c c} \hline \hline \(\mathbf{C_{rs}}\) & \textless{}19.0 & 19.0–28.0 & 28.0–40.0 & \textgreater{}40.0 \\ \hline Rockburst intensity & No rockburst & Weak rockburst & Moderate rockburst & Intense rockburst \\ \hline \hline \end{tabular}
\end{table}
Table 1: Intensity classification of rockburst index \(C_{rs}\).  
simulate the fracture of initiation, propagation, and interaction between blocks but also consider the various stress states of the surrounding rock. The visual analysis of the surrounding rock's multivariate information response, the rockburst intensity and its occurrence range, and the real simulation of the control effect of rigid structure plane on rockburst are realized under a three-dimensional stress state.