# A Comprehensive Safety Analysis Study for Concrete Core Dams
## 6 Conclusions  
Based on the research on the dangerous CCDDCR behavior, a typical example is selected as the research object. A seepage calculation method by FEM was proposed, and a 3-D nonlinear finite element model was developed. Based on FEM software, the SDAP program, and Li Zheng software, the seepage, stability, and other reinforcement behaviors \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Calculation Software** & \begin{tabular}{c} **Elastic Modulus** \\ **(MPa)** \\ \end{tabular} & \
\begin{tabular}{c} **Maximum Compressive** \\ **Stress (MPa)** \\ \end{tabular} &
\begin{tabular}{c} **Maximum Tension** \\ **Stress (MPa)** \\ \end{tabular} \\ \hline \multirow{5}{*}{SDAP} & 1000 & 0.95 & 0.21 \\  & 1500 & 1.09 & 0.47 \\  & 2000 & 1.28 & 0.76 \\  & 2500 & 1.33 & 0.92 \\  & 3000 & 1.49 & 1.09 \\  & 5000 & 2.22 & 2.01 \\  & 8000 & 3.12 & 2.43 \\ \hline \multirow{5}{*}{FEM} & 1000 & 0.81 & 0.28 \\  & 1500 & 0.88 & 0.41 \\  & 2000 & 1.06 & 0.56 \\  & 2500 & 1.14 & 0.74 \\  & 3000 & 1.24 & 0.87 \\  & 5000 & 2.10 & 1.87 \\  & 8000 & 3.32 & 2.31 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Stress and strain calculation results table under different elastic modulus for main dam. \begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline
**Material No.** & \(\mathbf{\gamma}\) & \(\mathbf{K}\) & \(\mathbf{K_{ur}}\) & \(\mathbf{n}\) & \(\mathbf{R_{f}}\) & \(\mathbf{c}\) & \(\mathbf{\varphi}^{\circ}\) & \(\mathbf{K_{0}}\) & \(\mathbf{G}\) & \(\mathbf{F}\) & \(\mathbf{d}\) \\ \hline
1 & 18.3 & 850 & 1020 & 0.40 & 0.75 & 0 & 30 & 0.47 & 0.36 & 0.16 & 6.0 \\
2 & 18.1 & 210 & 252 & 0.60 & 0.85 & 21.0 & 24 & 0.72 & 0.35 & 0.10 & 1.9 \\
3 & 18.2 & 950 & 1140 & 0.37 & 0.72 & 0 & 28 & 0.46 & 0.37 & 0.17 & 6.0 \\
4 & 10.8 & 750 & 900 & 0.41 & 0.75 & 0 & 30 & 0.48 & 0.35 & 0.16 & 6.0 \\
5 & 8.7 & 180 & 216 & 0.62 & 0.85 & 20.5 & 24 & 0.74 & 0.34 & 0.10 & 1.9 \\
6 & 10.7 & 860 & 1032 & 0.36 & 0.72 & 0 & 28 & 0.47 & 0.36 & 0.17 & 6.0 \\  & & 10,000 & 12,000 & & & & & & & 5000 & & \\  & & 15,000 & 18,000 & & & & & & & 7500 & & \\
7 & 22.0 & 20,000 & 24,000 & 0.00 & 0.00 & 0.00 & 500 & 30 & 0.00 & 10,000 & 0.00 & 0.0 \\  & & 30,000 & 36,000 & & & & & & & 15,000 & & 0.00 \\  & & 50,000 & 60,000 & & & & & & & 25,000 & & \\  & & 80,000 & 96,000 & & & & & & & 40,000 & \\ \hline \hline \end{tabular} Notes: \(\gamma\)—unit weight, kN/m\({}^{3}\); \(K_{0}\)—the coefficient of earth pressure at rest; the unit of \(\mathbf{c}\) is kN/m\({}^{2}\); material number in the table as follows: 1—mud sandy gravel of dam foundation; 2—core wall clay of dam; 3—sandy gravel; 4—mud sandy gravel of dam foundation after soaking; 5—core wall clay of dam after soaking; 6—sandy gravel of dam after soaking; 7—concrete diaphragm wall (\(\mathbf{E}\) = 1000 MPa, 1500 MPa, 2000 MPa, 3000 MPa, 5000 MPa, 5000 MPa, 8000 MPa).  
\end{table} 
Table 5: The material parameter table of main dam. are evaluated and analyzed, allowing for more reasonable conclusions. The proposed FEM method is validated for a good application to handle the dangerous CCDDCR. The research is based on the diaphragm wall material's low elastic modulus of concrete. Through a multi-group analysis, the influence law of the low elastic modulus of concrete materials on the cutoff wall is obtained to give reference to similar reinforcement projects. Conceptualization, M.Y. and C.G. ; methodology, D.W.; software, D.W.; validation, M.Y. ; formal analysis, M.Y. ; investigation, D.W.; resources, D.W.; data curation, D.W.; writing--original draft preparation, M.Y., D.W.; writing--review and editing, M.Y. All authors have read and agreed to the published version of the manuscript. This work was supported by the China Postdoctoral Science Foundation (Grant No.