## 3 Geological Background of Studied Rock Slopes  
### Geological Setting  
The study area is located in Zhejiang province, the southeastern coastal region of China with a continental area of 101,800 km\({}^{2}\). As shown in Figure 1, the hilly and mountainous terrain with elevation above 300 m accounts for 70.6% of its total area. The altitude decreases gradually from the southwest to the northeast and drops in a step form. The southwest part is a mountainous region with the existence of several peaks around 1000 m high. The central part is dominated by hills and scattered basins. The northeast portion is dominated by an alluvial plain. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \(\mathbf{H}\) & \(\mathbf{h}\) & \(\mathbf{I}\) & \(\mathbf{II}\) & \(\mathbf{III}\) & \(\mathbf{IV}\) \\ \hline \multirow{3}{*}{\(h_{1}\)} & \(h_{11}\) & 0 + 1.25\(I\) & 0.3 + 1.25\(I\) & 0.6 + 0.8333\(I\) & 0.8 + 0.8333\(I\) \\  & \(h_{12}\) & 0 + 1.25\(I\) & 0.3 + 1.25\(I\) & 0.6 + 0.8333\(I\) & 0.8 + 0.8333\(I\) \\  & \(h_{13}\) & 0 + 1.25\(I\) & 0.3 + 1.25\(I\) & 0.6 + 0.8333\(I\) & 0.8 + 0.8333\(I\) \\ \hline \multirow{3}{*}{\(h_{2}\)} & \(h_{21}\) & 0 + 0.4583\(I\) & 0.11 + 0.9167\(I\) & 0.33 + 1.4167\(I\) & 0.67 + 1.375\(I\) \\  & \(h_{22}\) & 0 + 0.5417\(I\) & 0.13 + 0.8333\(I\) & 0.33 + 1.4167\(I\) & 0.67 + 1.375\(I\) \\  & \(h_{23}\) & 0 + 1.25\(I\) & 0.3 + 1.25\(I\) & 0.6 + 0.8333\(I\) & 0.8 + 0.8333\(I\) \\ \hline \multirow{3}{*}{\(h_{31}\)} & \(h_{31}\) & 0 + 1.0417\(I\) & 0.25 + 1.0417\(I\) & 0.5 + 1.0417\(I\) & 0.75 + 1.0417\(I\) \\  & \(h_{32}\) & 0 + 1.25\(I\) & 0.3 + 1.25\(I\) & 0.6 + 0.8333\(I\) & 0.8 + 0.8333\(I\) \\ \hline \multirow{3}{*}{\(h_{33}\)} & \(h_{31}\) & 0 + 1.0417\(I\) & 0.25 + 1.0417\(I\) & 0.5 + 1.0417\(I\) & 0.75 + 1.0417\(I\) \\  & \(h_{32}\) & 0 + 1.25\(I\) & 0.3 + 1.25\(I\) & 0.6 + 0.8333\(I\) & 0.8 + 0.8333\(I\) \\ \cline{1-1}  & \(h_{33}\) & 0 + 1.0417\(I\) & 0.25 + 1.375\(I\) & 0.58 + 0.375\(I\) & 0.67 + 1.375\(I\) \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Subattributes of slopes expressed as neutrosophic number. This region suffers from complex geological and extreme climatic settings. Figure 2 shows the exposed bedrock in the mountainous area that consists mainly of intensely weathered granite and tuff [49]. With a geochemical process, the bedrock received strong weathering in this region. The degree of fragmentation alters from intact rock to gravel-like based on the degree of weathering. Generally, these weathering profiles have more complex engineering properties than other sedimentary soils [50]. Located in the coastal region, rainstorms are frequently encountered from May to October. The annual precipitation is around 1380 mm, and the maximum monthly precipitation of over 200 mm is typically recorded in June [51]. The weak geological properties and heavy rainfall brought by typhoon lead to geological disasters of great frequency and scale, which cost significant damages to lives and properties [52]. According to the geological investigation report in the research area from Department of Land and Resources of Zhejiang Province, 2832 geological disasters occurred in the recent five years, resulting in more than 50 civilian casualties as well as a direct economic loss of around US$40 million [53]. Prevention of geohazards is therefore of great importance in Zhejiang province. Similar disaster events have been reported worldwide, showing a strong demand for reliable field survey and instability assessment methods for disaster prevention [54,55]. To study the applicability of the developed method, a representative area in the central north of Zhejiang province was selected, which was located on a fault and was frequently struck by geohazards. A dataset of 20 rock slopes from 12 locations was collected through geologic survey as shown in Figure 3, where the data meet the requirements for the developed method. The study area is divided into two zones by the NE-striking Jiangshan-Shaoxing fault.