# Analysis of the Dynamic Stability of Tailing Dams:
## 3 Analysis of the Test Results
### Law of Dynamic Pore Pressure Development for Tailing silt under the Same CSR Conditions  
#### 3.2.1 Pore Pressure Development Law for Tailing silt at the Same CSR and Varied Confining Pressures  
As shown in Section 3.1, the sample's anti-liquefaction performance significantly rose as the consolidation pressure rose, and the anti-liquefaction strength gradually diminished as the dynamic load increased. However, if the test dynamic stress and consolidation confining pressure increase at the same time, the influence on the dynamic strength of the sample is still unclear. In this section, the combined impact of increasing confining pressure and dynamic load on tailing silt under the same CSR conditions is studied and the rule of pore pressure development is analyzed. As shown in Table 1, when the CSR was 0.17, and a confining pressure of 50, 100, 150, 200, 250, 300, 400, 600, or 1000 kPa was applied to the sample, the termination of cyclic vibrations was considered as 460, 190, 97, 35, 165, 295, 510, and 980, respectively, and the sample did not attain liquefaction at \(\sigma_{0}^{\prime}=100\) kPa. Figure 4 shows the cumulative pore water pressure growth curve of tailing silt at the same CSR and different confining pressures. The trend in pore pressure development in the tailing silt under different confining pressures was approximately the same, and at low confining pressures (\(\sigma_{o}^{\prime}\leq 200\) kPa), the rising dynamic load was the major factor in tailing silt vibration liquefaction. This is because when the confining pressure is low and the dynamic stress is small, the sample exhibits a certain strength; hence, the number of vibrations for the sample is relatively greater. As the confining pressure continued to increase, the applied dynamic stress also increased. At this stage, the gradually increasing dynamic stress continued to overcome the smaller binding effect of lateral pressure on soil particles under the lower confining pressure, resulting in an increase in dynamic stress as the dominant factor in sample liquefaction at this stage and the achievement of a critical state under \(\sigma_{o}^{\prime}=200\) kPa. In this phase, the rise in dynamic load has a larger effect on the sample's liquefaction resistance than the confining pressure does, and the sample's liquefaction rate steadily increases. As the confining pressure increased, the soil particles were compressed under a greater confining pressure (\(\sigma_{o}^{\prime}\geq 200\) kPa). The growing dynamic load at this stage was unable to overcome the binding effect of the lateral pressure on the soil particles under a greater confining pressure, resulting in the confining pressure increasing as the dominating factor of sample liquefaction at this stage. The number of vibrations necessary for liquefaction significantly rose as the confining pressure rose. When \(\sigma_{o}^{\prime}\) was 600 kPa, the number of vibrations necessary for liquefaction was 980, and the sample did not liquefy at \(\sigma_{o}^{\prime}=100\) kPa. This demonstrates that the impact of consolidation confining pressure on the sample's anti-liquefaction ability always dominates at high confining pressure and the anti-liquefaction potential of the sample gradually increases with the continuous increase in confining pressure. 2.2 Pore Pressure Development Law for Higher Density Tailing Silt at the Same CSR and Varied Confining Pressures  
With the CSR and other test conditions remaining the same, and only an increase in sample density \(\rho=1.67\) g/cm\({}^{3}\), a consolidation confining pressure of 50, 100, 150, 200, 300, or 600 kPa was applied to the high-density tailing silt samples. The required number of vibrations for liquefaction was 670, 220, 380, 650, or 1120, respectively, and the sample did not achieve liquefaction at \(\sigma_{o}^{\prime}=600\) kPa. It can be seen from Figure 5 that the pore pressure growth trend of tailing silt under two different density conditions in this experiment was similar.