# Numerical Simulation-Based Study on the Arching Effect in Subsequent Backfill
## 4 Analysis of the Influence of Backfill Dip Angle on Stress Distribution  
During the process of mining and backfilling in the mine, the stress distribution of the backfill body will directly affect the stability and safety of the stop. Especially in the inclined stope environment, the backfill body is not only affected by its own gravity, but also subjected to the compression of the surrounding rock of the upper plate and the restriction of the surrounding rock of the lower plate, thereby changing its internal stress transmission path and distribution characteristics. At present, there is still a lack of research  
Figure 11: Comparative analysis of the influence of interface element cohesion on stress distribution. on the arching effect of inclined filling bodies. The stress distribution law of stress arches under different inclination angles still needs further study. To explore in depth the stress distribution law of inclined filling bodies, with the aid of numerical simulation methods in this section, a systematic study was conducted on the arching effect at different inclinations. Numerical models of filling bodies with inclinations of 45\({}^{\circ}\), 60\({}^{\circ}\), 75\({}^{\circ}\), and 90\({}^{\circ}\) were established. The backfill body maintained consistent dimensions (60 m in length, 16 m in width, and 40 m in height) across all analyzed inclination angles The surrounding rock mass was modeled with an excavation influence zone extending three times the backfill dimensions to ensure proper boundary effects. The numerical simulation followed a sequential procedure: (1) initial excavation of the ore body to establish the mining-induced stress field, followed by (2) backfill placement and subsequent stress analysis. The vertical and horizontal stress distribution characteristics of these models were analyzed. Thus, it demonstrates the law that the change of inclination angle has an impact on the arching effect. The input parameters for the numerical simulation are consistent with those listed in Table 1 of Section 2.2. The stress profile obtained by numerical simulation and the comparison of stress values of the filling body at different inclination angles are shown in Figures 12 and 13. The numerical simulation results in Figure 12 clearly reveal the significant influence of the inclination angle variation of the filling body on the stress distribution. As the inclination angle of the filling body gradually increases from 45\({}^{\circ}\) to 60\({}^{\circ}\), 75\({}^{\circ}\) and up to 90\({}^{\circ}\), the stress field shows obvious redistribution characteristics: the compressive stress in the lower plate area gradually focuses on the bottom of the filling body, while the tensile stress in the upper plate area significantly migrates to the top. This evolutionary process indicates that the increase in the inclination angle will lead to two key effects: on the one hand, it will significantly intensify the stress concentration phenomenon at the bottom of the filling body; on the other hand, it will form an obvious tensile stress zone in the top area. This stress redistribution characteristic has an important influence on the stability of the filling body, especially under the condition of large inclination angle, the high stress concentration at the bottom and the tensile stress area at the top may become potential dangerous areas. It can be seen from the stress comparison in Figure 13 that when the inclination angle of the filling body increases from 45\({}^{\circ}\) to 90\({}^{\circ}\), there is an obvious regular change in the stress distribution at the center of the filling body. In terms of vertical stress data, when the inclination angles of the upper and lower plates of the filling body are 60\({}^{\circ}\), 75\({}^{\circ}\), and 90\({}^{\circ}\), the filling body at a height of 20 m is subjected to compressive stress. However, when the height is greater than 20 m, the center of the filling body gradually changes from compressive stress to tensile stress.