## 3 Model Building and Validation
### Different Sublevel Heights for the Sublevel Caving Method without the Sill Pillar  
The sublevel height is an important index that affects the workload when mining, the stability of the return roadway, and the stability of the fault, and the sublevel height of the sublevel method is usually the height of the return roadway plus the height of the fan-shaped shell hole. The segmentation height of the filling method consists of a number of layered heights. Different sublevel heights give different patterns of dynamic response to faults. By comparing the fault-related parameter indexes under the different segmentation heights of the bottomless column segmental sublevel method and the downward layered cementation filling method, we analyzed the evolution of the stress field and displacement  
Figure 7: GPS monitoring points for surface rock movement within the West Second Mining survey area.  
field of the surrounding rock and the fault surface in the process of mining the adjacent F8 fault, and then we analyzed the appropriate segmentation heights and the factors that have a great influence on the stability of the fault.  
The numerical simulation of mining was carried out by keeping an actual segmentation height of 20 m for the lower-layer filling method. The segmentation height of the sublevel cavity method without the sill pillar was set to 10 m, 15 m and 20 m, respectively. Due to the complexity of the mining situation in the field, the sublevel height was changed in the numerical simulation, but the height of the approach was not changed. The change in the fault dynamic response was analyzed, and it is shown in Figure 9.  
From the analysis of the above diagrams, it can be seen that the displacement range of the fault plane near the mining side was mainly distributed in the sublevel cavity method without the sill pillar and the filling method. The vertical displacement of the fault plane in the disintegration method was the largest, and it gradually decreased to the surrounding area. After mining, the vertical displacement of the fault surface at the filling method was about 0.6 m, and the maximum vertical displacement of the fault plane on the mining side could be up to 1.2977 m when the sublevel height of the sublevel cavity method without the sill pillar was 10 m; the maximum vertical displacement of the fault surface when the segmentation height of the sublevel cavity method without the sill pillar was 15 m was 1.4504 m, and that of the fault surface when the segmentation height was 20 m was 1.8139 m. With the increase in the segmentation height of the bottomless column segmented sublevel method, the fault surface would have the maximum displacement of the bottomless column segmented sublevel method, and the maximum displacement of the fault surface would be 1.8139 m. The vertical displacement of the fault face increases with  
Figure 8: Numerical simulation of surface displacement.  
the increase in the sublevel height, which indicates that the increase in the sublevel height of the sublevel method will lead to an increase in the instability of the fault; the positive stress on the fault face near the mining side was within the range of 10 MPa-25 MPa, and the local stress would suddenly increase to several tens of megapascals due to the mining process destroying the original stress field, and the value of positive stress would increase to 10 Mpa with the increase in the sublevel height of the sublevel method without the column. As the height of the sublevel saving method without the sill pillar increased, the value of positive stress also gradually increased, but there was no sudden change in the positive stress value.