## 7 Conclusions  
To evaluate the safety of constructing coal mine goaf sites for high-speed railways, this study employs the catastrophe progression technique to forecast the stability grade of coal mine goaf site, considers the high-speed railway load, and analyzes the influence of subgrade height, vehicle speed, and axle load on construction safety. An evaluation model on activation classification of coal mine goaf ground is proposed. This model primarily applies to level goaf areas using a longwall mining method at middle-deep depths, and it serves the purpose of assessing the activation grade of goaf ground under high-speed railways. The key conclusions are summarized below:  
1. The assessment and evaluation of ground activation in coal mine goaf for high-speed railway projects are divided into the influence of coal mine goaf site stability grade and the influence of high-speed railway engineering. The catastrophe progression method is introduced to predict the stability grade of the coal mine goaf site. The theoretical analysis and the establishment of the additional stress calculation model are used to classify the influence degree of the influencing factors of the high-speed railway project. The influence grade of different factors on the coal mine goaf site is categorized into four grades: no influence, low influence, medium influence, and high influence. 2. The influence of the stability grade of the coal mine goaf site as well as the influence of the high-speed railway project are comprehensively considered via the extension comprehensive evaluation method. This method is simple, accurate, and overcomes the shortcomings of the general algorithm weight selection with strong human subjectivity and subjective evaluation results. 3. A constructed system for evaluating the stability of coal mine goaf sites incorporates the catastrophe progression technique to evaluate the grade of stability. The factors influencing the stability grade of coal mine goaf site are determined, and the stability grade classification includes stable, basically stable, less stable, and unstable. Through the verification of the example, the accuracy of this method can reach 96.7%. 4. The analysis and evaluation results of engineering examples are 'activation', aligning with the conclusions presented in the engineering evaluation report. This shows that the evaluation results of activation in high-speed railway coal mine goaf ground based on catastrophe progression method-extension comprehensive evaluation method are accurate and reliable, which provides a new way for evaluating the activation of the foundation in high-speed railway goaf. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Evaluation Methods** & **Weight Calculation Methods** & **Advantages** & **Disadvantages** \\ \hline ANP-entropy weight-fuzzy & & The use of entropy weighting & Too much reliance on \\ comprehensive evaluation method [35] & Expert scoring method & reduces the error of human & questionnaires, questionable \\  & & subjective factors & authenticity of questionnaires \\  & & & Using the expert scoring \\  & & & method to determine the \\  & & factor affiliation & weight, the human subjective \\  & & & error is large \\  & & & The neural network method \\  & & Uncertainty measurement & Eliminate the error of & does not fit well with the \\  & & theory & human factors & topologically integrated \\  & & & evaluation method \\  & & Bottom tier indicator weights & The calculation of the bottom & \\  & & are determined by the impact & index weights is objective, and & \\  & & degree (few relevant studies), & the first layer of index weights & The application of catastrophe \\  & & and first tier indicator weights & is determined by combining & progression method requires a \\  & & refer to others’ results (many & engineering experience, with & larger sample size \\  & & relevant studies and & a simple calculation process & \\  & & wide application) & and accurate results & \\ \hline \hline \end{tabular}
\end{table} 
Table 12: Comparisons of different methods.