## 3 Results and Discussion
### Monitoring Results  
The traditional monitoring method (total station) and digital image photogrammetry (digital camera) were applied in the field for 7 months. In addition, cellphone-based digital image photogrammetry was applied in the field for 4 months. Therefore, this section describes the comparison results of traditional monitoring methods (total station) and digital image photogrammetry (digital camera and cellphone) using the results of field monitoring experiments. Table 3 shows the results of the field monitoring conducted for 7 months. The values presented in the table have the following meanings. The 3D coordinates of traditional monitoring and digital image photogrammetry represent the results measured using the total station and digital camera, respectively. The values in the columns of 'Variation Analysis Of Traditional Monitoring' and 'Variation Analysis Of Digital Photogrammetry' are the results obtained by converting each 3D coordinate into a displacement vector. Moreover, 'Difference' represents the difference between each displacement vector. Figure 8: Electrical resistivity survey results: (**a**) ER-1-1 and ER-1-2; (**b**) ER-1-3; (**c**) ER-1-4; (**d**) ER-2-1; (**e**) ER-2-2 and ER-2-3. Figure 9: Corner crack status of the MSE wall. \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline
**Elapsed** **Time** **(Drop)** & **Measurement** & \multicolumn{3}{c}{**Traditional Monitoring (Total Station)**} & \multicolumn{3}{c}{**Digital Photogrammetry**} & \multicolumn{3}{c}{**V Variation**} & \multicolumn{3}{c}{**Variation**} \\ \cline{2-10}
**Time** **(Drop)** & **Position** & **X** & **Y** & **Z** & **\(N^{\prime}\)** & **Z**\({}^{\prime}\)** & **M**onitoring & **Digital Photogrammetry** & **(mm)**  
Based on the measurement results, the elapsed time-displacement relationship according to the position of the wall facing was plotted, as shown in Figure 10.  
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline
**Hepepep** & \multirow{2}{*}{**Measurement**} & \multicolumn{3}{c}{**Traditional Monitoring**} & \multicolumn{3}{c}{**Digital Photogrammetry**} & \multirow{2}{*}{**Variation**} & \multirow{2}{*}{**Variation**} & \multirow{2}{*}{**Variation**} & \  
First, the total station measurements were analyzed. It was found that the displacement at STA.80 ranged from a minimum of 1 mm (STA.80_2, STA.80_4) to a maximum of 18.815 mm (STA.80_5). The change in displacement over time showed similar shapes for STA.80_1-STA.80_5, but the displacement at STA.80_5 was larger than that at the other points. The height of the measurement point STA.80_5 was 5.2 m from the bottom of the MSE wall, which was approximately 37% of the total height of the MSE wall (14.1 m). It is typical for the wall facing deformation of an MSE wall to have the largest deformation in the first one-third segment of the total height (approximately 33% of the total height). This implies that STA.80_5 had a larger deformation at the corner. The displacements at STA.85 were found to range from a minimum of 1.414 mm (STA.85_2, STA.85_4) to a maximum of 21.471 mm (STA.85_5). The evolution of the displacement over time and quantitative displacement values were found to be almost similar for all points, and the displacement at STA.85 was slightly larger than that at STA.80 for less than one-third of the total height. This agreed with the analysis of the cause of the displacement at STA.80. The digital image photogrammetry results, obtained using a digital camera, were analyzed. The displacement at the corner of STA.80 was found to be a minimum of 3.606 mm (STA.80_1) and a maximum of 24.536 mm (STA.80_5). The temporal changes in the displacement were similar for STA.80_1 to STA.80_5. However, the quantitative displacement values were somewhat larger than the displacement values for the total station, and some were irregular. In particular, the displacements at STA.80_4 and STA.80_5 were found to be large.