# Effect of Wetting Conditions on the In Situ Density of Soil Using the Sand-Cone Method
## 2 Density Tests Using Sand-Cone Method
### Artificial Ground and Test Procedure  
To examine the effect of a moist ground on the sand-cone method, artificial test holes with three shapes (cylindrical, conical, and roof-shaped) and with depths of 10 and 15 cm were used. Detailed sizes and shapes of the holes are shown in Figure 4. The soil was obtained from a construction site located at Youngchun, Kyungbuk Province, Korea, and compacted into a test vessel with a diameter of 41.5 cm and a height of 17 cm. The soil properties are shown in Table 3. The soil was thoroughly mixed with a specific amount of water (2, 7, 12, and 16% of the weight of the soil). The wetness of a compacted ground was simulated based on the field conditions of road and railway embankments in Korea; wetness levels of 2, 7, 12, and 16% were defined as slightly wet, wet, moderately wet, and completely wet, respectively. Subsequently, the moist soil was compacted in a vessel whose weight and volume were known. As shown in Figure 5a,b, a plate with the dimensions 14.5 cm \(\times\) 14.5 cm \(\times\) 2 cm was placed on the soil, and three-layer compaction was performed using a 2.5-kg rammer, with a drop height of 30 cm and 15 blows per layer. The small rammer was used to compact the areas which were not in contact with the plate, especially the edges. After compaction, the entire test vessel was weighed to determine the bulk density of the compacted soil.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Specific** & **D60** & **D30** & **D10** & **Coefficient of** & **Coefficient of** & **Unified Soil** \\
**Gravity, Gs** & **(mm)** & **(mm)** & **(mm)** & **Uniformity, C\({}_{\textbf{u}}\)** & **Curvature, C\({}_{\textbf{c}}\)** & **Classification System** \\ \hline
2.65 & 0.62 & 0.45 & 0.31 & 2.00 & 1.06 & SP \\ \hline \hline \end{tabular}
\end{table}
Table 2: Soil-physical properties of Jumunjin sand.  
Figure 3: Grain-size distribution curve for the Jumunjin sand used in this study.  
The compacted soil was dug to form the same size hole as the artificial hole. The soil was dug until it fitted into the hole frame by putting the frame into the digging hole. Subsequently, the sand-cone method was used (Figure 5c), and the test hole was filled with the sand (Figure 5d). Meanwhile, kaolinite was mixed with the soil to investigate whether voids due to the sand sticking appeared, regardless of the soil type. The mixture was compacted to make an artificial ground that has the same shape as Figure 2. The kaolinite used in this study was the same kaolinite used by [PERSON] and [PERSON] [6], and the liquid limit (LL) and plastic limit (PL) of the kaolinite were 60% and 40%, respectively. It was mixed at a ratio of 0.2, 0.4, 0.6, 0.8, and 1.0 to the soil, and the moisture contents of compacted grounds used were 16% at a ratio of 0.2 and 0.4 and 20% at 0.6, 0.8, and 1.0, respectively.  
The effect of moist sand filling was investigated by adding moisture to the test sand. The moisture content was gradually increased to 0.8% of the weight of dry sand. A 10-cm deep cylindrical test hole made of a galvanized iron sheet was used, and its volume was determined using the water-filling method [2]. The sand-cone method was used to  
Figure 4: Detailed sizes and shapes of artificial holes (cylinder (**a**), cone (**b**), and roof (**c**); unit: cm).  
Figure 5: The test procedure (**a**): detailed compaction process, (**b**): compacted soil and rammer, (**c**): sand-cone method tools, and (**d**): the hole filled with test sand).  
determine the mass of the moist sand required to fill the test hole, and the volume and density of the sand were then calculated.