Research Of Rockburst Risk Comprehensive Evaluation Method Based On Unascertained Measurement Model And Application

With the increase in mining intensity and depth during the last few years, the number of rockburst mines and the impact damage has increased significantly. As extremely complex dynamic phenomena, rockbursts are serious threat to safety and production in coalmines. It has great significance for mine safety to evaluate and forecast rockbursts timely and accurately. Based on considering the problems and deficiencies in current rockburst risk evaluation methods and statistics analysis of many burst instances occurring in different coalmines, this paper systematically analyzed the influencing factors of rockburst from burst tendency of coal or rock, geological factors and mining technology conditions and selected corresponding evaluation indexes, and then established the comprehensive evaluation index system of burst risk. In this paper, the analytic hierarchy process (AHP) method was used to calculate the weight of each index and the unascertained mathematics was applied to burst risk evaluation for the first time, and then the burst risk comprehensive evaluation model based on the unascertained measure theory was established.(1) By collecting many burst instances occurring in different coalmines and statistical analysis of existing literatures, this paper analyzed the causes, characteristics and various influencing factors of bursts, and divided these influencing factors into three aspects including burst tendency of coal or rock, geological factors and mining technology conditions, and provided a basis to establish the comprehensive evaluation index system and evaluation model of burst risk.(2) By using many methods such as theoretical analysis, experimental study, and numerical simulation and so on, this paper systematically analyzed the influences of the burst tendency of coal or rock, geological factors and mining technology conditions on rockburst risk, and selected geologic structure index, water content of coal,injection angle of coal, concentration factor of advance stress, distance between the stress maximum and coal wall and mining velocity rationality as new evaluation indexes. Then divided the whole evaluation structure into three levels including general target, first level factors and the decomposition of the first level factor, according to the principle of AHP, and established the evaluation index system of burst risk.(3) This paper analyzed different uncertain information existing in burst risk comprehensive evaluation, including random information, fuzzy information, gray information and uncertain information. Based on the principle of error analysis, analyzed the uncertain information source from data acquisition error, data processing error and human error, and analyzed the manifestation of uncertain information.(4) Aiming at different kinds of uncertain information, this paper applied the unascertained mathematics to burst risk comprehensive evaluation for the first time, established the evaluation model of burst risk based on unascertained measure and compiled the corresponding application software. According to related regulations, classified the burst risk into no risk, medium risk and strong risk and also judged the risk grade of comprehensive evaluation indexes. For the difference between quantitative indexes and qualitative indexes, established respective unascertained measure function by different methods and constructed single index measure model and multiple index measure model, and then judged the burst risk by confidence discriminant method.(5) On the basis of above research, the burst risk comprehensive evaluation method based on unascertained measure was used to evaluate the burst risk of coalface of Changgouyu coalmine and Nanshan coalmine, and the evaluation result was in good agreement with mining facts. The results show that the unascertained measure model has excellent practicality and accuracy.