# Experimental and Empirical Studies to Evaluate Liquefaction Resistance of Partially Saturated Sands
## 3 Materials and Methods
### Speciment Preparation  
In this study, nearly/fully saturated and partially saturated sand specimens with a height/diameter ratio of about 2 were prepared in loose or dense conditions. For the cylindrical triaxial specimens, a porous stone and filter paper was positioned in the bottom part of the cell (base pedestal), and a rubber latex membrane was installed using a pair of O-rings. A rigid split mold (140 mm in height and 70 mm in diameter) was used to support the specimens. Such was applied with a vacuum pump to remove air between the membrane and mold and to hold them together. The reconstituted, uniform, dry sand specimens were prepared inside the mold. The air (dry)-pluviation method was used for the loose specimens, while the dry-tamping method was chosen for the densely packed sand specimens. A filter paper, porous stone, and top adaptor (cap) were placed over the specimens, and membrane ends were sealed with another pair of O-rings. Vacuum pressure (e.g., 20 kPa) was applied to the specimens so that they could stand up by themselves and  
Figure 2: Particle size distribution curve for Sile sand and its comparison with different types of sand and liquefaction boundaries suggested by [PERSON] [52].  
remain undeformed following the removal of the split mold. The triaxial cell was carefully lowered over the specimens and filled with water. The specimens were kept under suction until an effective confining stress of 20 kPa was applied by increasing the cell pressure. Figure 3 shows examples of test images recorded during the specimen preparation.  
For the nearly/fully saturated sand tests, the dry specimens set in the triaxial cell and subjected to effective confining stress of 20 kPa were flushed with carbon dioxide gas. This process was repeated with de-aired water. For the partially saturated sand tests, the dry specimens under an effective confining stress of 20 kPa were flushed with a known volume of sodium percarbonate-water solution. This solution was prepared by mixing finely powdered sodium percarbonate with de-aired water in specified ratios. The chemical compound of sodium percarbonate reacted with water (for 1 day) and generated oxygen bubbles inside the pore spaces of specimens, which produced a partially saturated condition. The degree of saturation (\(S_{r}\)) of the specimens was adjusted by changing the initial concentration of the solution. Details of the specimen-preparation procedure in partially saturated sands were elaborated in Zeybek [57].  
\begin{table}
\begin{tabular}{l l l} \hline \hline
**Properties of Sand** & **Value** & **Test Standard** \\ \hline Average particle size, \(D_{50}\) (mm) & 0.296 & \\ Coefficient of gradation, \(C_{c}\) & 0.974 & ASTM, D6913/D6913M-17 [53] \\ Uniformity coefficient, \(C_{u}\) & 1.352 & \\ Specific gravity, \(G_{s}\) & 2.65 & ASTM, D854-14 [54] \\ Minimum void ratio, \(e_{min}\) & 0.574 & ASTM, Method 1A, D4253-16e1 [55] \\ Maximum void ratio, \(e_{max}\) & 0.885 & ASTM, Method A in D4254-16 [56] \\ Soil classification & SP & Unified Soil Classification System (USCS) \\ \hline \hline \end{tabular}
\end{table}
Table 1: The index properties of Sile sand.  
Figure 3: Examples of test images recorded during the specimen preparation.