# Research on an Evaluation Method of Snowdrift Hazard for Railway Subgrades
## 3 Project Overview and Results
### Risk Assessment Results  
Using the fuzzy comprehensive evaluation (FCE) model, the snowdrift hazard assessment for the Afu Railway has resulted in hazard zoning as shown in the table. The high-risk sections are areas with strong wind forces and deep snow accumulation at the snow source, which meet the natural conditions for snowdrift occurrence, and the subgrade design parameters in these areas significantly exacerbate the severity of snowdrift disasters. Through comprehensive fuzzy calculations and normalization processing of the snowdrift hazard risks for the Afu Railway, the comprehensive fuzzy judgment sets for each working condition are obtained as follows:  
1. DK27 + 600 Hazardous Fuzzy Judgment Set: \[\widetilde{B}_{1}=(0.0497,\,0.0410,\,0.3749,\,0.1740,\,0.0947)\] (23) where \(\widetilde{\text{b}}_{103}=0.3749\); it is determined that the hazard level at DK27 + 900 is classified as Level III, indicating a moderate state of risk. 2. DK65 + 900 Hazardous Fuzzy Judgment Set: \[\widetilde{B}_{2}=(0.0254,\,0.0658,\,0.1507,\,0.1230,\,0.4772)\] (24) where \(\widetilde{\text{b}}_{105}=0.4772\); it is determined that the hazard level at DK65 + 900 is classified as Level V, indicating a very high risk. \begin{table}
\begin{tabular}{l c c c c c} \hline \hline \multirow{2}{*}{**Index**} & \multicolumn{6}{c}{**Index Membership**} \\ \cline{2-6}  & **I** & **II** & **III** & **IV** & **V** \\ \hline Topographic slope (\(U_{11}\)) & 0 & 0 & 1 & 0 & 0 \\ Vegetational cover (\(U_{12}\)) & 0 & 0 & 0 & 0 & 1 \\ Wind direction (\(U_{31}\)) & 0 & 0 & 0 & 0 & 1 \\ The average snow thickness (\(U_{21}\)) & 0 & 0 & 0 & 1 & 0 \\ Annual snowfall (\(U_{22}\)) & 0 & 0 & 0 & 1 & 0 \\ Snow duration (\(U_{23}\)) & 0 & 0 & 0 & 1 & 0 \\ Mean wind velocity (\(U_{32}\)) & 0 & 0.4958 & 0.5041 & 0 & 0 \\ Mean wind velocity (\(U_{32}\)) & 0 & 0 & 0.4931 & 0.5069 & 0 \\ Maximum wind velocity (\(U_{33}\)) & 0 & 0 & 0 & 0 & 1 \\ Wind duration (\(U_{34}\)) & 1 & 0 & 0 & 0 & 0 \\ Embankment height(\(U_{41}\)) & 0 & 0 & 0 & 0 & 1 \\ Cutting depth (\(U_{42}\)) & 0 & 0 & 0 & 0 & 0 \\ \hline \hline \end{tabular}
\end{table} 
Table 10: Indicator membership of DK198 + 200. \begin{table}
\begin{tabular}{l c c c c c} \hline \hline \multirow{2}{*}{**Index**} & \multicolumn{6}{c}{**Index Membership**} \\ \cline{2-5}  & **I** & **II** & **III** & **IV** & **V** \\ \hline Topographic slope (\(U_{11}\)) & 0 & 0 & 1 & 0 & 0 \\ Vegetational cover (\(U_{12}\)) & 0 & 0 & 0 & 0 & 1 \\ Wind direction (\(U_{31}\)) & 0 & 0 & 0 & 0 & 1 \\ The average snow thickness (\(U_{21}\)) & 0 & 0 & 0 & 1 & 0 \\ Annual snowfall (\(U_{22}\)) & 0 & 0 & 0.5055 & 0.4945 & 0 \\ Snow duration (\(U_{23}\)) & 0 & 0 & 0 & 1 & 0 \\ Maximum wind velocity (\(U_{32}\)) & 0 & 0 & 0 & 0 & 1 \\ Wind duration (\(U_{34}\)) & 1 & 0 & 0 & 0 & 0 \\ Embankment height (\(U_{41}\)) & 0 & 0 & 0 & 0 & 0 \\ Cutting depth (\(U_{42}\)) & 0 & 0 & 1 & 0 & 0 \\ \hline \hline \end{tabular}
\end{table} 
Table 9: Indicator membership of DK135 + 200. * DK135 + 200 Hazardous Fuzzy Judgment Set: \[\widetilde{B}_{3}=(0.0497,\ 0,\ 0.4349,\ 0.1124,\ 0.261)\] (25) where \(\widetilde{\text{b}}_{03}=0.4349\); it is determined that the hazard level at DK135 + 200 is classified as Level III, indicating a moderate state of risk. * DK198 + 200 Hazardous Fuzzy Judgment Set: \[\widetilde{B}_{4}=(0.0497,\ 0.0082,\ 0.1023,\ 0.1570,\ 0.402)\] (26) where \(\widetilde{\text{b}}_{05}=0.402\); it is determined that the hazard level at DK198 + 200 is classified as Level V, indicating a very high risk. Validation by method described in Table 3, the maximum membership degrees of the four monitoring points are all valid (Table 11), which confirmed the accuracy of the results. The hazard levels of snowdrift disasters are as indicated above, all falling into a state of risk, with particular attention to DK65 + 900 and DK198 + 200, which are classified as Level V zones. It shows that the method is consistent with actual field measurements in comparison with on-site observations.