## 3 Results and Discussion
### Monitoring Results
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{3}{*}{**Elapsed Time** **(Days)**} & \multirow{3}{*}{**Measurement** **Point**} & **Variation** & **Variation** & **Variation** & **Difference between** & **Difference between** \\  & & **Analysis of** & **Analysis of** & **Analysis of Digital** & **Traditional** & **Traditional** \\  & & **Traditional** & **Digital Image** & **Image** & **Monitoring and** & **Monitoring and** \\  & & **Monitoring** & **Photogrammetry** & **Digital Image** & **Digital Image** & **Digital Image** \\  & & **(Total Station)** & **(Digital Camera)** & **(Cellphone** & **Photogrammetry** & **Photogrammetry** \\  & & **(mm)** & **(mm)** & **(mm)** & **(mm)** & **(mm)** \\ \hline \multirow{6}{*}{0} & 80\_1 & 0.000 & 0.000 & 0.000 & 0.000 & 0.000 \\ \cline{2-7}  & 80\_2 & 0.000 & 0.000 & 0.000 & 0.000 & 0.000 \\ \cline{2-7}  & 80\_3 & 0.000 & 0.000 & 0.000 & 0.000 & 0.000 \\ \cline{2-7}  & 80\_4 & 0.000 & 0.000 & 0.000 & 0.000 & 0.000 \\ \cline{2-7}  & 80\_5 & 0.000 & 0.000 & 0.000 & 0.000 & 0.000 \\ \cline{2-7}  & 85\_1 & 0.000 & 0.000 & 0.000 & 0.000 & 0.000 \\ \cline{2-7}  & 85\_2 & 0.000 & 0.000 & 0.000 & 0.000 & 0.000 \\ \cline{2-7}  & 85\_3 & 0.000 & 0.000 & 0.000 & 0.000 & 0.000 \\ \cline{2-7}  & 85\_4 & 0.000 & 0.000 & 0.000 & 0.000 & 0.000 \\ \cline{2-7}  & 85\_5 & 0.000 & 0.000 & 0.000 & 0.000 & 0.000 \\ \hline \multirow{6}{*}{31} & 80\_1 & 11.225 & 11.747 & 20.025 & 0.522 & 8.800 \\ \cline{2-7}  & 80\_2 & 12.083 & 17.059 & 12.884 & 4.976 & 0.801 \\ \cline{2-7}  & 80\_3 & 13.748 & 14.457 & 12.369 & 0.709 & 1.378 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Monitoring results using traditional monitoring and digital image photogrammetry (4 months). Figure 11: Difference between displacements obtained using the traditional monitoring method and digital camera-based digital image photogrammetry. Figure 12 shows a plot of the elapsed time and the displacement of each measurement point obtained using traditional monitoring and digital image photogrammetry methods. Figure 12a,b show the results of the traditional monitoring method. Despite the differences between the displacement values of the neighboring STA80 and STA85, a similar trend  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Elapsed Time** **(Days)**} & \multirow{2}{*}{**Measurement**} & \multirow{2}{*}{**Variation**} & \multirow{2}{*}{**Variation**} & \multirow{2}{*}{**Variation**} & \multirow{2}{*}{**Difference between**} & \multirow{2}{*}{**Difference between**} \\  & & Analysis of** & & & **Analysis of Digital** & & **Traditional** \\  & & & & **Digital Image** & & **Monitoring and** & **Monitoring and** \\  & & **Point** & **Monitoring** & **Photogrammetry** & **Photogrammetry** & **Digital Image** & **Digital Image** \\  & & **(Total Station)** & **(Digital Camera)** & **(Digital Camera)** & **(Cellphone** & **Photogrammetry** & **Photogrammetry** \\  & & **(mm)** & **(mm)** & **Camera)** & **(Digital Camera)** & **(Cellphone Camera)** \\ \hline \multirow{8}{*}{31} & 80\_4 & 13.928 & 17.720 & 12.207 & 3.792 & 1.722 \\ \cline{2-7}  & 80\_  
was observed in the temporal changes in the displacement. The minimum and maximum displacements at STA.80 and STA.85 were 3.162-13.928 mm and 4.472-18.412 mm, respectively. As shown in Figure 12c,d, the measurement results of the digital camera-based digital image photogrammetry showed that the minimum and maximum displacements of STA.80 were 2.236 mm and 17.747 mm, and the minimum and maximum displacements of STA.85 were 3 mm and 21.424 mm. In particular, the displacement values at 120 days were found to be relatively much larger than those obtained via traditional monitoring. Figure 12e,f show the digital image photogrammetry measurements obtained using the cellphone camera. Regardless of the monitoring area, the displacement occurrence trend was similar to that of traditional monitoring and the digital camera with respect to the initial elapsed time, but the measurements were very irregular thereafter.