## 4 Results and Analysis
\begin{table}
\begin{tabular}{c c c} \hline \hline \(A\) & \(A_{1}\) & \(A_{2}\) & \(A_{3}\) & \(A_{4}\) \\ \hline \(A_{1}\) & 1 & 1/5 & 1/5 & 6 \\ \(A_{2}\) & 5 & 1 & 1 & 3 \\ \(A_{3}\) & 5 & 1 & 1 & 5 \\ \(A_{4}\) & 1/6 & 1/3 & 1/5 & 1 \\ \hline \hline \end{tabular}
\end{table} 
Table 8: Judgment matrix of geological condition indicators. \begin{table}
\begin{tabular}{c c c} \hline \hline \(A_{1}\) & \(A_{2}\) & \(A_{3}\) & \(A_{4}\) \\ \hline \(A_{1}\) & 1 & 1/5 & 1/5 & 6 \\ \(A_{2}\) & 5 & 1 & 1 & 3 \\ \(A_{3}\) & 5 & 1 & 1 & 5 \\ \(A_{4}\) & 1/6 & 1/3 & 1/5 & 1 \\ \hline \hline \end{tabular}
\end{table} 
Table 9: Judgment matrix of geological condition indicators. Subsequently, the judgment matrix is tested for consistency by Formulae (12) and (13). When the judgment matrix passes the consistency test, the normalized relative weight of each index relative to the upper-level index can be calculated by Formula (11). The single weight value of each level index is integrated with the weight of the category to which it belongs, and the comprehensive weight set of 15 evaluation indices is obtained, as shown in Table 12. For the criterion layer, the weight is \(C>A>D>B>E\), which indicates that the concrete material \(C\) used in the tunnel and the hydrological situation \(A\) in the construction area have a higher impact on the crystallization blockage of the drainage system. In contrast, the geological situation, drainage facility \(D\), and the environment \(E\) in the tunnel have a lower impact on the crystallization blockage of the drainage system. In these five factors, the concrete materials, drainage, and tunnel environment can be controlled by human means (are controllable factors), and hydrological and geological conditions are uncontrollable factors. Among the controllable factors, the concrete material has the greatest influence on the crystallization problem of the tunnel drainage system, which indicates that, in the early stage of tunnel construction, the crystallization blockage problem of the drainage system of the mountain tunnel can be improved by adjusting the relevant design ratio parameters of the concrete material. Relevant scholars [34] have also tried to conduct research in this regard. \begin{table}
\begin{tabular}{c c c c} \hline \hline \(D\) & \(D_{1}\) & \(D_{2}\) & \(D_{4}\) \\ \hline \(D_{1}\) & 1 & 1 & 1/7 \\ \(D_{2}\) & 1 & 1 & 1/7 \\ \(D_{4}\) & 7 & 7 & 1 \\ \hline \hline \end{tabular}
\end{table} 
Table 10: Judgment matrix of drainage facility indicators. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{\ \begin{tabular}{c} **Indicator** \\ **Layer** \\ \end{tabular}  } & \multicolumn{4}{c}{\(A\)-\(E\) Weight Distribution**} & \multirow{2}{*}{ \begin{tabular}{c} **Comprehensive** \\ **Weight of Each** \\ **Index** \\ \end{tabular}  } \\ \cline{2-5}  & **0.321** & **0.091** & **0.433** & **0.118** & **0.037** & **Index** \\ \hline \(A_{1}\) & 0.134 & & & & 0.043 \\ \(A_{2}\) & 0.376 & & & & 0.1  
Figure 3 is the ranking result of these 15 indicators according to their respective weights. According to the size of the weights, the 15 indicators are divided into three intervals. In the comprehensive weight interval [0.100, 0.250], the order of the weights is \(C_{1}>C_{2}>A_{3}>A_{2}\). In the comprehensive weight interval [0.040, 0.100], the order of the weights is \(D_{4}>B_{1}>C_{4}>A_{1}\). In the comprehensive weight interval [0.000, 0.040], the order of the weights is \(E_{1}>C_{3}>A_{4}>B_{2}>D_{1}>D_{2}>E_{2}\). The following conclusions can be drawn from the weight ranking of each interval. The interval [0.100, 0.250]  
The compactness of concrete \(C_{1}\) and the content of Ca in cement \(C_{2}\) are the important reasons that affect the crystallization blockage of drainage systems in a mountain tunnel. For these two controllable factors, the purpose of reducing the amount of crystallization can be achieved by adjusting the water-cement ratio and cement type, respectively, in the construction process.