## 2 Numerical Simulation of CSG Dam upon Overburden
### Analysis of Factors Affecting Characteristics  
There have been many studies on the influence of dam material properties on the stress-strain characteristics of CSG dam. However, there are relatively few studies on the influence of geometric properties such as dimensions and shape of dam, as well as material properties of the overburden, on the characteristics of stress and displacement of CSG dams. A sensitivity analysis of the input parameters can provide insight into the numerical simulation model's robustness and the significance of various parameters. The change in slope coefficient will have a significant impact on the distribution of internal stress in the dam, and the change in the characteristics of the overburden will cause changes in the deformation of the dam body above it, leading to changes in stress. Meanwhile, based on the requirements of optimizing the design of the dam's section in the following text, this paper selects six parameters: the upstream and downstream slope coefficients (\(m=1/i\), \(i\) is the slope ratio, \(m\) is the slope coefficient) of the first and second stages of the dam body, the elastic modulus of the overburden, and the Poisson's ratio of the overburden. The study focuses on the influence of these six factors on two characteristic values: the maximum settlement and the maximum compressive stress of the dam body during the impounding period. The first four factors are geometric parameters of the dam body, while the last two factors are material properties of the overburden. To make the tables and figures more concise, abbreviations are used to refer to various parameters. Among them, the downstream slope coefficient of the second stage of the dam is represented by \(m_{1}\), the upstream slope coefficient of the second stage of the dam body is represented by \(m_{2}\), the downstream slope coefficient of the first stage of the dam body is represented by \(m_{3}\), and the upstream slope coefficient of the first stage of the dam body is represented by \(m_{4}\), as shown in Figure 7. \(E_{ob}\) refers to the elastic modulus of the overburden, \(\mu_{ob}\) refers to the Poisson's ratio of the overburden, \(y_{dummy}\) refers to the maximum settlement of the dam body, \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Project**} & \multirow{2}{*}{\begin{tabular}{c} **Maximum** \\ **Displacement in** \\ **the X Direction** \\ **(cm)** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Maximum** \\ **Settlement in the** \\ **Y Direction (cm)** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Maximum** \\ **Compressive** \\ **Stress (MPa)** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Maximum Tensile** \\ **Stress (MPa)** \\ \end{tabular} } \\ \hline \multirow{4}{*}{Completion period} & \multirow{2}{*}{\begin{tabular}{c} Value \\ **Position** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} 0.132 (along the river direction) \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} 4.143 \\ \end{tabular} } & \multirow{2}{*}{\
\begin{tabular}{c} 2.451 \\ \end{tabular} } & \multirow{2}{*}{
\begin{tabular}{c} 0.702 \\ \end{tabular} } \\ \cline{3-3} \cline{5-6}  & & & & & \\ \cline{3-3} \cline{5-6}  & & & & & \\ \cline{3-3} \cline{5-6}  & & & & & \\ \cline{3-3} \cline{5-6}  & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Characteristic values and positions of the dam body. and \(\sigma_{dammx}\) refers to the maximum compressive stress of the dam body. The influencing factors and working conditions of this experiment are shown in Table 4.  
As shown in Figure 8a, the maximum settlement of the dam body increases with the increase in the four slope coefficients, that is, whether it is the first or second stages of the dam body, upstream or downstream, the maximum settlement of the dam body increases with the decrease in their slope.