# Analysis of Slope Stability in Ion-Adsorption Rare Earth Mine Under In Situ Leaching Condition
## 3 Results and Discussion
### Effect of Liquid Injection on the Stability of Rare Earth Mine Slope  
The leaching solution is continuously injected into the ore body through the leaching agent injection wells during in situ leaching. This process facilitates the exchange of cations in the ammonium sulfate solution with adsorbed rare earth ions [39; 40]. During this process, the leaching solution causes fine particles to disperse and migrate from the top to the bottom of the rare earth mine soil, decreasing the local relative content of fine clay minerals. This alters the pore structure and pore size of the rare earth mine soil, further impacting its physical and mechanical properties. Consequently, the strength of the soil diminishes, and slope stability is compromised [41].  
Utilizing different analytical methods to compare the results of the safety factor enables a more reasonable prediction of slope stability. If the safety factors obtained by these methods show significant variation, it indicates issues with the engineering model. Otherwise, it confirms the model's validity. Various methods, such as Bishop's, Morgenstern-Price, and [PERSON]'s, were employed to study the transient stability of the rare earth mine slope under self-weight, groundwater, and injection conditions in this study. The [PERSON] method, grounded in [PERSON]'s strength theory, employs circular slip surface analysis to simplify slope stability to a plane strain problem. A safety factor K is assumed, and it is then back-calculated. Iterative calculations ensure that the error in F is controlled within a specified range. The Morgenstern-Price method posits a functional relationship between normal and tangential interslice forces in the horizontal direction. It employs the slice method to analyze the forces acting on the sliding soil mass. The [PERSON] method posits that the ratio of horizontal to vertical forces on the sides of soil slices is constant, resulting in parallel resultant forces between slices. This method is used to determine the slope stability safety factor. The seepage calculation results from the SEEP/W module were input into the SLOPE/W module to determine the slope stability safety factors for saturated and unsaturated soils. This analysis revealed the changes in safety factors over time during the initial conditions and the main stages of leaching and push-water operation.  
The comparison of the three analytical methods in Figure 6 shows that the safety factors derived are largely consistent. This suggests that the influence of the calculation method on the slope safety factor is minimal. For instance, the results from the Morgenstern-Price method indicate that the safety factor of the rare earth slope decreases initially and then increases with the duration of leaching. Before leaching operations, the safety factor is 1.790. After 5 days, it slightly decreases to 1.753, showing minimal change from the initial condition. By 10 days, the safety factor drops to 1.663 as the leaching solution starts to weaken the geotechnical strength of the slope, significantly affecting stability. A sharp decline in the safety factor follows, attributed to the amount of leaching solution and the duration of injection increase, the moisture content in the soil significantly rises, creating extensive areas of high pore pressure. The leaching solution drastically reduces the slope's cohesive force, and under high moisture content conditions, the soil's shear strength mainly depends on the internal friction angle. Additionally, a substantial amount of the leaching agent within the slope increases the slope's weight. The above analysis also indicates that the impact of leaching on the slope unfolds over time, exhibiting a certain degree of lag. The safety factor remains above 1.1 throughout the leaching process, indicating the stability of the slope. As the amount of push water decreases, the safety factor increases again.