## 4 Discussion  
There is no doubt that the single-source information assessment method can also assess the risk of tunnel collapse. However, a single source of information does not fully reflect the environment of tunnel construction, resulting in a certain deviation and low accuracy of the assessment results. In order to compare the single information source method and the multi-source information fusion method, the single information source model, \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Sample** & **Classifier** & **Probability** & **Probability** & **Probability** & **Probability** & **Predicted** & **True Label** & **Description** \\
**Index** & **Outputs** & **over Level I** & **over Level II** & **over Level III** & **over Level IV** & **Label** & **True Label** & **Description** \\ \hline \multirow{8}{*}{No. 1} & E1 & 0.35 & 0.45 & 0.1 & 0.1 & II & I & \\  & E2 & 0.4 & 0.2 & 0.1 & 0.3 & I & I & \\  & E3 & 0.5 & 0.3 & 0 & 0.2 & I & I & \\  & D-S & 0.68 & 0.26 & 0 & 0.06 & I & I & \\  & Improved D-S & 0.5 & 0.3 & 0 & 0.2 & I & I & \\ \hline \multirow{8}{*}{No. 2} & E1 & 0.15 & 0.7 & 0 & 0.15 & II & II & \\  & E2 & 0.25 & 0.55 & 0.1 & 0.1 & II & II & \\  & E3 & 0 & 0.3 & 0.6 & 0.1 & III & II & \\  & & K = 0.884, = [0.5, 0.33, 0.6], r = [0.741, 0.790, 0.791] & & & & \\  & D-S & 0 & 0.9 & 0 & 0.1 & II & \\  & Improved D-S & 0 & 0.8 & 0.2 & 0 & II & II & \\ \hline \multirow{8}{*}{No. 3} & E1 & 0.1 & 0.2 & 0.1 & 0.6 & IV & III & \\  & E2 & 0 & 0.2 & 0.8 & 0 & III & III & K = 0.968 \(>\) 0.95. \\  & E3 & 0.2 & 0.6 & 0.1 & 0.1 & II & III & Only the result \\  & & K = 0.968, = [0.5, 0.33, 0.6], r = [0.763, 0.834, 0.892] & & & & of Improved \\  & D-S & 0 & 0.75 & 0.25 & 0 & II & III & D-S is correct. \\  & Improved D-S & 0 & 0.33 & 0.67 & 0 & III & III & \\ \hline \multirow{8}{*}{No. 4} & E1 & 0.06 & 0.6 & 0.2 & 0.14 & II & II & \\  & E2 & 0.08 & 0.52 & 0.3 & 0.1 & II & II & \\  & E3 & 0.04 & 0.1 & 0.5 & 0.36 & III & II & \\  & & K = 0.862, t = [0.5, 0.33, 0.6], r = [0.801, 0.735, 0.834] & & & & \\  & D-S & 0 & 0.9 & 0.1 & 0 & II & \\  & Improved D-S & 0 & 0.8 & 0.2 & 0 & II & II & \\ \hline \multirow{8}{*}{No. 5} & E1 & 0.1 & 0.1 & 0.65 & 0.15 & III & III & \\  & E2 & 0.3 & 0.4 & 0 & 0.3 & II & III & K = 0.9735 \(>\) 0.95. \\  & E3 & 0 & 0.1 & 0.4 & 0.5 & IV & III & Only the result \\  & & K = 0.9735, t = [0.5, 0.33, 0.6], r = [0.733, 0.685, 0.707] & & & & \\  & D-S & 0 & 0.15 & 0 & 0.85 & IV & III & D-S is correct. \\  & Improved D-S & 0.1 & 0.2 & 0.4 & 0.3 & III & III \\ \hline \multirow{8}{*}{No. 6} & E1 & 0 & 0.18 & 0.2 & 0.62 & IV & IV & \\  & E2 & 0.1 & 0.3 & 0.5 & 0.1 & III & IV & \\ \cline{1-1}  & E3 & 0.02 & 0.1 & 0.28 & 0.6 & IV & IV & \\ \cline{1-1}  & & K = 0.874, t = [0.5, 0.33, 0.6], r = [0.786, 0.779, 0.834] & & & & \\ \cline{1-1}  & D-S & 0 & 0 & 0.2 & 0.8 & IV & IV & \\ \cline{1-1}  & Improved D-S & 0 & 0.05 & 0.15 & 0.8 & IV & IV & \\ \hline \hline \end{tabular}
\end{table} 
Table 10: Fusion results of the probability over classes for six samples. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Evidence** & **Level** & **Precision** & **Recall** & **Specificity** & **F1-Score** & **Support** \\ \hline \multirow{8}{*}{E1} & I & 0.62 & 0.5 & 0.89 & 0.55 & 16 \\  & II & 0.74 & 0.68 & 0.83 & 0.71 & 25 \\  & III & 0.56 & 0.6 & 0.84 & 0.58 & 15 \\  & IV & 0.38 & 0.75 & 0.91 & 0.5 & 4 \\  & I & 0.6 & 0.56 & 0.86 & 0.58 & 16 \\  & II & 0.68 & 0.6 & 0 the traditional multi-source information fusion method and the improved multi-source information fusion method are used to evaluate the collapse risk. The risk assessment of 60 tunnel sections in Wenbishan Tunnel is conducted, and the evaluation results of different models are shown in Figure 6. In order to illustrate that the proposed method can improve the high conflict evidence, the high conflict risk of YK223 + 473 tunnel section in the fault zone is evaluated and analyzed.