For the dilemma of insufficient mining of rock burst precursor information in excavation roadway of steeply inclined ultra-thick coal seam,the evolution law of multiple physical indicators was explored based on the early warning of the mining roadway of steeply inclined ultra-thick coal seam in Wudong Coal Mine,Xinjiang Province.Four machine learning algorithms,including BP neural network,random forest(RF),support vector machine(SVM)and gradient lifting decision Tree(GBDT),were adopted.The prediction models of rock burst in excavation roadway of steeply inclined ultra-thick coal seam are established respectively,the prediction perfor-mance of each model is verified and the case analysis is carried out,and the sensitivity distribution of each index under the excavation of steeply inclined ultra-thick coal seam based on neural network algorithm is clarified.The results show that the machine learning algorithm can effectively extract the impact precursor features contained in the development trend of each physical index,among which the modeling accuracy of BP neural network algo-rithm is the highest.When compared with other models,the average absolute error reduced by 58.44%,55.64%and 26.37%,respectively,and the R2 increased by 11.25%,8.37%and 3.66%,respectively.Under the geological conditions of the excavation roadway of steeply inclined ultra-thick coal seam,the sensitivity order of each physi-cal index obtained by BP neural network algorithm is A(b)value,b value,S value of mine seismic activity,EEM value of equivalent energy level parameter,earthquake absence value,and algorithm complexity AC value.The R-value scoring method is applied to verify the efficiency of the rockburst warning of the excavation roadway in Wudong Coal Mine,and the results show that the prediction accuracy of the model is good,the overall prediction accuracy is 90.65%,and two large energy events during the excavation are successfully predicted.The method used is suitable for the rockburst warning of the excavation roadway in excavation roadway of steeply inclined ultra-thick coal seam.The established model has a good potential for predicting rock burst risk,and the research results can provide reference for the evolution and development of rockburst risk in steeply inclined coal seam.
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