Improved catastrophe progression method of underground goaf risk evaluation

In order to solve the problem of underground goafs, particularly in light of the importance ranking of evaluation indices being more subjective and catastrophe progression values being large and too concentrated in the catastrophe progression method, the importance of multiple indices is ranked by the maximizing deviation method. An S-shaped curve is used to establish a regression function to improve the value of catastrophe progression method. First, three first-level evaluation indices and eight second-level evaluation indices are selected to establish an index system for risk evaluation of the underground goaf. Next, based on the principle of catastrophe progression method, an improved catastrophe model for its risk evaluation is established. Finally, sample training and verification are performed based on the improved evaluation model. The evaluation results show that the improved catastrophe progression method objectively ranks the importance of the evaluation indices of each layer, which improves the credibility of the evaluation results. The evaluation results are consistent with the actual geological data and detection results, which verifies the validity and accuracy of the evaluation model. However, only 87.5% of the risk levels obtained by the fuzzy comprehensive evaluation method are completely consistent with the improved catastrophe progression method, and the ranking error of risk value within one rank also accounted for 87.5%. Therefore, the results calculated by the improved catastrophe progression method are more accurate. The numerical gap of the improved catastrophe progression values becomes larger, from [0.796, 0.969] to [0.275, 0.691], which is 2.405 times of the interval difference of the catastrophe progression values before the improvement, which makes the numerical distribution of the catastrophe progression values more scientific and reasonable, with a higher resolution level. Therefore, it is reasonable and feasible to use the improved catastrophe progression method for the risk evaluation of the underground goaf, which can provide a certain theoretical basis and engineering guidance for underground goaf disaster control and management.