Study On Comprehensive Evaluation Method Of Rock Burst In Mine

The reason for the burst of rockburst in the mine is the system response process under the dual action of internal and external factors.The traditional rockburst risk assessment is mostly based on empirical evaluation and qualitative evaluation.There is a lot of uncertainty.Therefore,it is of great practical value and research significance to establish a rockburst evaluation system and carry out a comprehensive evaluation of rockburst risk.Firstly,field investigation,laboratory mechanical performance test and literature statistics are carried out on the influencing factors of rock burst.The coal samples taken in the field survey are cut and processed in the laboratory and then subjected to impact tendency identification test,and four impact tendencies are obtained.The characteristic index parameters are coal seam elastic energy index,impact energy index,dynamic failure time,and uniaxial compressive strength,respectively,and the study area is determined to be at weak impact risk.By analyzing the rockburst evaluation method,various indexes used for rockburst evaluation in previous literatures were collected,and a comprehensive rockburst evaluation system was constructed.The Delphi method is used to select 34 evaluation indicators,and the correlation analysis is used to screen the primary indicators,and 16 evaluation indicators are determined to construct a comprehensive evaluation index system of rock burst.Secondly,quantify the evaluation indicators,and treat the original data with the same trend and normalization.The evaluation index is subjected to the subjective weight of the Analytic Hierarchy Process(AHP)and the objective weight of the entropy weight method(EWM),and then the Euclidean distance function is introduced to obtain the CW combination weight.The TOPSIS method is introduced to rank the proximity of the limited evaluation objects to the idealized targets,and a CW-TOPSIS comprehensive evaluation model of rockburst based on combined weights is constructed.Comprehensive analysis of various influencing factors of rockburst occurrence,establishment of rockburst grade evaluation criteria system,established evaluation index system and CW-TOPSIS comprehensive evaluation model,the research results are in the rockburst evaluation process of the 18-2 working face of a mine It has been successfully applied,and according to the hazard level classification standard,it is concluded that the working face is a weak impact hazard.Third,from a macro perspective,the possibility index method is used to evaluate the impact risk to verify the evaluation results of the comprehensive evaluation model,and the possibility of an accident is judged by calculating the membership degree of a certain stress state and the impact tendency.It is learned that the 18-2 working face has the conditions for the occurrence of rock bursts,and there is a danger that rock bursts may occur.The evaluation results of the possibility index method are consistent with the comprehensive evaluation model.Finally,the FLAC3 D numerical simulation-assisted comprehensive evaluation model of rockburst is used to predict the dangerous area.By simulating the stress distribution and evolution law in the study area,it is predicted that the stress concentration phenomenon in the mining process is mainly concentrated in the roof area above the working face.