## 2 Test Program
### Test Procedures  
As shown in Figure 1, the cyclic tests were carried out using the TYD-20 dynamic triaxial test apparatus, which can apply dynamic load with various waveforms and measure real-time data including dynamic stress, dynamic strain, and dynamic pore water pressure of the soil samples under long-term cyclic loading. The following is a list of detailed test procedures. Figure 1: TYD-20 dynamic triaxial test apparatus. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Number**} & **Fine Particle** & **Effective Axial Stress** & **Drainage Conditions** \\  & **Content/\%** & **Paths/kPa** & **(Cyclic Tests)** \\ \hline AU/AD-1 & 7 & 100 & Undrained/Drained \\ AU/AD-1 & 8 & 100 & Undrained/Drained \\ AU/AD-1 & 10 & 100 & Undrained/Drained \\ AU/AD-1 & 12 & 100 & Undrained/Drained \\ AU/AD-1 & 14 & 100 & Undrained/Drained \\ \hline BU-1 & 8 & 100\(\rightarrow\)90\(\rightarrow\)80\(\rightarrow\)70\(\rightarrow\)60 & Undrained \\ BU-2 & 8 & 100\(\rightarrow\)80\(\rightarrow\)60 & Undrained \\ BU-3 & 8 & 100\(\rightarrow\)60 & Undrained \\ \hline CU-1 & 8 & 100\(\rightarrow\)90\(\rightarrow\)80\(\rightarrow\)70\(\rightarrow\)60\(\rightarrow\)100 & Undrained \\ CU-2 & 8 & 100\(\rightarrow\)80\(\rightarrow\)60\(\rightarrow\)100 & Undrained \\ CU-3 & 8 & 100\(\rightarrow\)60\(\rightarrow\)100 & Undrained \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Test scheme. Sample preparation  
The required weight of the silt and kaolin clay was calculated based on the parameters of the soil samples, including a dry density of 1.497 g/cm\({}^{3}\), diameter of 39.1 mm, height of 79.8 mm, and fine particle content. However, the soil sample with 28.91% water content liquefies easily in the compaction process. The compaction curve was obtained, and the optimum water content and maximum dry density were 26% and 1.523 g/cm\({}^{3}\), respectively. The dry density of the reconstituted silt under 22% water content was 1.497 g/cm\({}^{3}\), which is close to the dry density of in-situ silt. As a result, the de-aired water was added based on the controlled water content of 22%. The compaction method was chosen in accordance with the Specification of Soil Test (GB/T50123-2019) to ensure the uniformity of the soil sample. The soil samples were compacted into five layers, and the interface between adjacent layers was scraped to ensure good contact. Saturation  
The soil sample was placed in the vacuum pumping cylinder and saturated using the vacuum saturation method. The negative pressure was maintained at 100 kPa, and de-aired water was slowly injected from the bottom of the soil sample. After the sample was completely submerged in water, draining was stopped, and air extraction was continued for another half hour. The valves were then closed completely. Consolidation  
To ensure isotropic consolidation, the confining pressure was set at 100 kPa and the axial force was set at 120 N. The soil sample was installed in the pressure chamber, and then water was injected and pore water pressure was zeroed. The confining pressure was added, and the consolidation was started after the pore water pressure had stabilized and the check saturation had reached the specified value. The original height and maximum pore water pressure were recorded, and then the drainage valve was kept open until the pore water pressure had dropped by more than 95%. The total axial stress of the soil sample was unloaded in multiple stages according to the test scheme after initial consolidation. In the reloading stress path, the axial stress was increased to its initial value. All unloading and reloading rates were set to 1 kPa/min. The drainage valve was continuously open and the sample was allowed to be completely consolidated after each stage of unloading and reloading. The stress amplitude, number of cycles, data acquisition time interval, and termination conditions were all set at the start of the cyclic loading process. For the drained tests, the drainage valve was kept open, and for the undrained tests, it was closed.