Electromagnetic wave CT evaluation method for rock burst hazard in near field based on rock burst start-up process

In recent years,with the gradual increase of mining depth and intensity,the frequency of rock burst disaster increases year by year,which seriously threatens the safety of mine production. Currently,the risk assessment method is based on field measurement only accounting for energy accumulation,which leads to the failure of the evaluation re- sults to reflect all rock burst hazards in the field. In this study,three stages of energy release,energy transfer and shock appearance were considered. On the basis of the electromagnetic wave CT detection platform,through theoretical research,a rock burst start-up probability of the four indexes was proposed,including the fusion energy concentration in- dex,the support damage index,the yield close index and the energy transfer attenuation index,by combining the yield proximity and unloading coupling theory with the impact pressure theory. Also,the weight of each index was deter- mined,including attribute weight set according to the difference degree of each index value,and grade weight set ac- cording to the risk level of each index. A multi-factor comprehensive evaluation model for rock burst hazard was estab- lished,and then a multi-factor evaluation method for near-field surrounding rock burst hazard was established,and the method was implemented by programming. In the 207 return airway of Tingnan Mine in China,it was found that the ar- rangement of roadway in the section of coal pillar greatly increased the stress concentration of the coal pillar area, which leads to the higher degree of support damage and the larger plastic zone,and has a higher impact risk. Using this method,the field measured data of 207 working face in Tingnan Coal Mine were processed,which was found that the distribution of roadway in the section of coal pillar increased the degree of stress concentration in the coal pillar area, and leaded to the higher degree of support damage. The larger plastic zone range,and the higher rock burst hazard. The drilling cuttings method was used to verify the effectiveness of the impact risk assessment method based on impact start-up process. Compared to the rock burst hazard assessment method of surrounding rock in the past,the rock burst start-up probability evaluation method proposed comprehensively considered the influence of multiple factors,improved the identification degree of the rock burst hazard area,and provided a more accurate basis for the roadway rock burst control. Especially,for the coal pillar area,it is of significance in application.