## 5 Numerical Simulation of Blasting Hole Network Parameters  
### Model Establishment  
The model is established with the blasting area in the study area as the modeling object. In order to make the numerical simulation results close to the actual blasting, the slope model is established for the blasting area. The charging method is the continuous decoupling charge with the decoupling coefficient of 2.82. The starting point is set at the bottom of the charge. The height of the model is 14 m and the width is 10 m. The two blast holes of each group of models are set at the midpoint of the symmetric boundary surface at the top of the slope. The model is established as shown in Figure 9. The two boreholes of each model are set at the midpoint of the symmetric boundary surface at the top of the slope. In addition to the calculation of the symmetric boundary of the model, they are set as a non-reflective boundary. The keyword * BOUNDARY_NON_REFLECTION is used to define. Figure 8: Field blasting effect. Figure 6: Chart of charge structure of each hole. Figure 7: Site construction process. The section of the borehole is set as the symmetric boundary, and * BOUNDARY_SPC_SET is used to define. In this triaxial compression test, the rock in the mining area of Inner Mongolia was selected as the test material. The large rock was processed into seven cylindrical specimens by a cutting machine. The seven specimens were polished by a grinding machine, so that the end surface roughness error was not greater than 0.015 mm. The specimen after compression is shown in Figure 10, and the rock material coefficient is shown in Table 2.  
In the simulation calculation, the plugging material should be selected as soil and foam because of the compaction during filling and the compression of blasting stress. The gap inside the material is large, but there will be a certain stiffness of the material after compression. At the same time, it is also to ensure the accuracy of the calculation results. The coefficient of plugging material and the coefficient of emulsion explosive material are shown in Tables 3 and 4. In order to facilitate the observation of the unit failure of rock mass under blasting, four observation points are arranged between the two borehole walls, and each observation point is not coplanar. The plugging and observation point setting are shown in Figure 11. \begin{table}
\begin{tabular}{c c c c c} \hline \hline Density \(\rho\) & Modulus of Elasticity & Poisson’s Ratio & Yield Strength & Tangent Modulus \\ g/cm\({}^{3}\) & E/GPa & v & MPa & GPa \\ \hline
2.43 & 156 & 0.26 & 3 & 11.3 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Rock material coefficient table. Figure 10: Compression results of specimens. Figure 9: Model diagram. Reasonable hole network parameters can not only make the blasting effect more efficient but also effectively reduce the harmful effect generated during blasting operation. In the case of other blasting parameters unchanged, only change the size of the pre-splitting blasting hole diameter and hole distance; according to the actual geological conditions and production conditions of the mine, the overall model height is 1400 cm, width is 1000 cm, hole depth is 1100 cm, charge length is 800 cm, hole diameter is 90-130 mm, and the hole distance is 7-12 times the hole diameter, producing a total of 30 groups for the calculation model. After the modeling process is completed, the sat file is imported into Hypermesh 14.0 for meshing. Since the blast hole is in a symmetric position, and the slope model is also large, half of the model is removed when meshing, and then, the symmetric command is used to restore the mesh. The overall analysis model is shown in Figures 3 and 5. After meshing, it is necessary to define the material for each regional element mesh: the blue area is the rock element mesh, the yellow area is the blockage element mesh, the purple is the air domain element mesh, and the sky blue and red are the explosive element mesh.