# Landslide Displacement Prediction Based on Variational Mode Decomposition and GA-Elman Model
## 3 Research Area  
### General State of the Engineering Geology of the Shuizhuyuan Landslide  
The Shuizhuyuan landslide was located in Group 1 of Ganju Village, Quchi Township, Wushan County, on the left bank of the Yangtze River (31\({}^{\circ}\)00\({}^{\prime}\)59.37\({}^{\prime\prime}\) E, 109\({}^{\circ}\)43\({}^{\prime}\)27.33\({}^{\prime\prime}\) N). It was 14.82 km away from the new urban area of Wushan and 170 km away from the Three Gorges Dam in the east (Figure 2).  
The elevation of the rear edge of the landslide was 350 m and the elevation of the front edge was 90 m; the front edge was submerged below the water level of the reservoir area at 145 m. The relative elevation difference was 260 m, and the main sliding direction was 150\({}^{\circ}\). The landslide had a length of about 800 m, a width of 360-1200 m, an average thickness of 30 m, an area of 62 \(\times\) 10\({}^{4}\) m\({}^{2}\), and a volume of 1850 \(\times\) 10\({}^{4}\) m\({}^{3}\). The landslide potentially threatened 375 people in 65 households (191 permanent residents) and the safety of shipping in the Yangtze River. In 2002, it was found that there was a crack, 300 m long and 2-3 cm wide, in the middle and rear edge of the landslide. In May 2003, it was first found that the upper house (adobe house) had signs of cracking and deformation, with a maximum crack size of 20 cm. Since the monitoring work was carried out in 2006, the landslide deformation has generally shown a nearly uniform creep deformation trend. The main deformation characteristic is that the deformation of the front edge of the landslide was large, and the deformation of the rear edge was relatively small. Small collapses occurred at the wading part of the front edge of the landslide, showing obvious deformation characteristics of a traction landslide.  
The sliding mass was composed of loose Quaternary deposits. The engineering geological profile of the landslide is shown in Figure 3. The bedrock outcrop section in the middle-lower part of the landslide comprised siltstone and silty mudstone of the Middle  
Figure 2: Location of the Shuizhuyuan landslide.  
Triassic Badong Formation (T\({}_{2}\)b). The exposed stratum in the middle and trailing edge of the landslide was Upper Triassic Xuijahe Formation (T\({}_{3}\)xj) sandstone. The sliding zone material of the landslide was mainly silty clay, due to the sliding zone being filled with water and softer plastic, which are prone to sliding deformation. On the basis of the above analysis, the landslide could be characterized as a soil landslide with precipitation and reservoir as the main inducing factors.  
Therefore, the main aspects of the landslide that require monitoring are surface displacement, rainfall, change in the reservoir water level, and macro patrol monitoring. Seven GNSS deformation monitoring points and one GNSS reference point were identified on the landslide, forming three longitudinal monitoring profiles, one rainfall monitoring point, and one point for monitoring reservoir water level change using the collected data. The layout plan of the monitoring network is shown in Figure 4. Since the deployment of the monitoring equipment, a continuous state of deformation has been observed in the landslide; the deformation of the middle front edge on the left side of the landslide was relatively strong. The Shuizhuyuan landslide is a typical landslide located in the Three Gorges Reservoir area. It is of great significance to analyze it and accurately predict its development.  
Figure 4: Layout plan of the Shuizhuyuan landslide monitoring network.  
Figure 3: The engineering geological profile of the Shuizhuyuan landslide.