Assessment of rock burst risk in roadway based on the combination of seismic and electromagnetic wave CT technology

The electromagnetic wave CT can detect the heading face,but cannot detect the large area behind the head-ing. The seismic wave CT can detect the coal body of mining face,but cannot detect the pillars on both sides. There is a blind evaluation area in the mining roadway for the impact risk assessment based on single CT detection method. To overcome the practical problems mentioned above,an evaluation method of mining roadway impact hazard based on the combined detection of seismic wave and electromagnetic wave CT was established. Combining the electromagnetic wave CT with the seismic wave CT,the mathematical expression of impact hazard evaluation method based on two kinds of CT detections was researched. Time and position were taken as state variables,the internal logic relationship and im-plementation process of the evaluation method were determined by taking the field dynamic performance and CT detec-tion results as driving variables. Through the analysis of the mechanics foundation of impact risk assessment based on the seismic wave and the electromagnetic wave CT detection,the model of impact risk assessment was established. On the basis of two kinds of CT detections,the determination of the impact risk grade and the division of the dangerous ar-ea in the mining roadway were realized. The combination of survey methods had realized the determination of danger-ous grade and the division of dangerous area in the heading face and large area behind it,mining face and coal pillar area. The validity of the evaluation method was verified. This method overcomes the limitation of evaluation method based on a single CT detection method in detection scale,and almost covers all potential dangerous impact areas in the mining roadway. It provides a more accurate basis for the treatment of rock burst and has a better application effect. In terms of time,the method combines the CT detection with mine excavation,determines the detection sequence prelimi-narily,and adjusts it according to the actual dynamic performance and the results of the last CT detection. In terms of space,it covers almost all the potential impact dangerous areas in the mining roadways such as heading face,mining face and coal pillars,and basically guarantees no evaluation blind areas. Moreover,the method makes full use of the convenience of the operation process of vibration wave and electromagnetic wave CT detection,and has a good adapta-bility to the sudden onset of field dynamic manifestation.