# Research on Grading Evaluation of Coal and Gas Dynamic Disasters Based on Fuzzy Mathematics
## 4 Results and Discussion
### Grading Evaluation and Verification
#### 4.3.2 Analysis of the Grading Evaluation Results  
Using the grading evaluation method based on fuzzy mathematics, grading evaluation was conducted on CGDDs at different distances from the open-off cut (128 m, 247.5 m, 299.4 m, and 435 m) in the 1010201-working face of the No. 1 Well of the Yuwang Coal Mine. The evaluation results are compared with the test results of the drill cuttings gas desorption indicator (\(K_{1}\) value) and drill cuttings volume (\(S\) value), as shown in Table 6. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Parameter** & **Characteristic Indicators and Scoring Matrix** & **Eigenvector** & **Maximum Eigenvalue** & **Consistency Ratio (C.R.)** \\ \hline \hline mining disturbance stress factor set \(U_{1}\) & \(v_{p}\) & \(A_{n}\) & \(\backslash\) & & & \\  & \(v_{p}\) & 1 & 0.67 & \(\backslash\) & 0.4 & 2.0025 & \(\backslash\) \\  & \(A_{n}\) & 1.5 & 1 & \(\backslash\) & 0.6 & & \\ \hline gas dynamic emission factor & \(U_{2}\) & \(A\) & \(B\) & \(D\) & \(\backslash\) & & \\  & \(A\) & 1 & 3 & 2.8 & 0.6 & & \\  & \(B\) & 0.33 & 1 & 0.9 & 0.2 & 3.0948 & 0.0817 \\ set \(U_{2}\) & \(D\) & 0.36 & 1.1 & 1 & 0.2 & & \\ \hline  & \(U_{1}\) & \(U_{1}\) & \(U_{2}\) & \(\backslash\) & \(\backslash\) & & \\  & \(U_{1}\) & 1 & 0.67 & \(\backslash\) & 0.4 & 2.0025 & \(\backslash\) \\  & \(U_{2}\) & 1.5 & 1 & \(\backslash\) & 0.6 & & \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Score matrix and calculation of characteristic indicators for each level. Table 6 presents the evaluation results of different assessment methods at various distances from the open-off cut. * When the distance is 128 m, the area is classified as a threat zone based on the single indicator \(B\). However, according to the fuzzy mathematics method and the maximum drill cuttings gas desorption indicator (\(K_{1}\) value) and drill cuttings volume (\(S\) value) obtained from field investigations, it is identified as a normal zone. * At a distance of 247.5 m, the area is categorized as a threat zone based on the single indicator \(v_{p}\) or \(B\). In contrast, the fuzzy mathematics method and field investigation results indicate that it should be classified as a dangerous zone. * When the distance reaches 299.4 m, the single indicator \(A_{n}\) or \(D\) classifies the area as dangerous. However, the fuzzy mathematics method and field measurements suggest classification to a threat zone instead. * At a distance of 435 m, the single indicator \(B\) identifies the area as dangerous, while the single indicator \(D\) suggests it is a normal zone. Nevertheless, based on the fuzzy mathematics method and the maximum drill cuttings gas desorption indicator (\(K_{1}\) value) and drill cuttings volume (\(S\) value) from field investigations, the area is ultimately assessed as a threat zone. The primary source of uncertainty in the data collection process for the gas desorption indicator of the drill cuttings gas desorption indicator (\(K_{1}\) value) and drill cuttings volume (\(S\) value) arises from human factors. Although field operations strictly follow standardized procedures, minor human errors may still occur during data recording and processing. To mitigate these uncertainties, repeated measurements were conducted throughout the data collection process, enhancing the reliability and accuracy of the obtained data. In conclusion, using a single indicator for the grading evaluation of CGDDs may lead to contradictory results. However, the evaluation results obtained using the fuzzy mathematics method align with those from the field investigation. Furthermore, when the evaluation results of a single mining disturbance stress and the characteristic indicator of gas dynamic emissions are contradictory, the evaluation results from the fuzzy mathematics method are consistent with the characteristic indicator of gas dynamic emission, which indicates that the weight distribution ratio of the mining disturbance stress factor set \(U_{1}\), and the gas dynamic emission factor set \(U_{2}\) is appropriate.