## 5 Analysis of Numerical-Simulation Results
### Comparison of seepage-Simulation Test Results for Filters with Different Particle Shapes
With the exception of 0.075-0.25 mm tailings-sand particles, for other particle sizes, the proportion of infiltrating particles and the depth of infiltration for the spherical-particle filter layer were greater than those for the ellipsoidal-particle filter layer. Figures 16-18 illustrate various forms and the evolution of clogging in the filter layer during muddy-water seepage. For the uniform filter layer ranging from 2 to 5 mm, 0.5-1 mm tailings-sand particles were concentrated above the filter layer and at a depth of 15-20 cm within the first layer of the filter layer, indicating surface-internal deposition. Most of the 0.25-0.5 mm tailings-sand particles were retained at a depth of 15-20 cm within the first layer of the filter layer, while a small amount continued to migrate to 10-15 cm within the second layer, indicating internal clogging. For the 0.075-0.25 mm tailings particles, although Figure 18 suggests that the clogging morphology was similar to that of the 0.25-0.5 mm tailings particles, this similarity arises from the significant size difference between the 0.075-0.25 mm particles and the filter layer. The finite element software processes data very slowly, making it challenging to reach an equilibrium state, and observations and calculations indicate that the infiltration of tailings particles of this size exerts minimal influence on the filter layer's permeability coefficient, which is why only a portion of the calculation results are presented. In fact, because the tailings-sand particles were significantly smaller than the pore diameter of the filter layer, the filter layer cannot provide effective filtration of the tailings-sand particles; the result is the eventual passage of tailings-sand particles through the filter layer, a form of seepage failure. Figure 17: The proportion of 0.25-0.5 mm turbid-water particles in different positions in the filter layer. Through Equations (1)-(3) and (5), the maximum and minimum effective pore radii for both the spherical-particle filter layer and the ellipsoidal-particle filter layer were calculated. The theoretical effective pore radius for the spherical-particle filter layer was 0.31-2.07 mm, whereas that for the ellipsoidal-particle filter layer was 0.11-4.12 mm. It can be observed that the effective pore radius of the ellipsoidal-particle filter layer exhibited a wider range of variation and that the maximum effective pore radius of the ellipsoidal-particle filter layer exceeded that of the spherical-particle filter layer. The observations from Figures 16-18 indicate that the effective pore radius of the ellipsoidal-particle filter layer was greater than that of the spherical-particle filter layer. This suggests that the permeability of the ellipsoidal-particle filter layer was likely greater than that of the spherical-particle filter layer, a conclusion that was validated through the analysis of the permeability coefficient of the filter layer. The Process of Changing the Permeability Coefficient of Filter Layers with Different Particle Shapes  
The permeability coefficient of the model cannot be directly obtained using PFC and must be calculated by employing appropriate theoretical formulas. In this paper, the  
Figure 18: The proportion of 0.075-0.25 mm turbid-water particles in different positions in the filter layer. Darcy permeability coefficient Equation (18) was employed to estimate the permeability coefficient, and the results of these calculations were subsequently analyzed. \[k=v/i \tag{18}\]  
In the equation, \(v\) represents the seepage velocity, while \(i\) denotes the hydraulic gradient. The calculated permeability coefficients for filters with varying particle shapes are presented in Figures 19-21. In the figures, SP represents a spherical-particle filter layer, whereas EL denotes an ellipsoidal-particle filter layer. Analysis of Figures 19-21 indicates that, based on the results derived from [PERSON]'s formula, the permeability coefficient of the spherical particle model is lower than that of the ellipsoidal particle model.