Method for Ground Penetrating Radar Identification of Intercalated Gangue Layers during Complex Structure Coal Seam Tunneling

During complex coal seam tunneling, the interlayer gangue impacts mining equipment cutting operations. Identifying interlayer gangue positions is crucial for guiding the advanced control of the cutting arm swing speed. This paper proposes a ground penetrating radar (GPR) method that accurately calculates gangue volume within the maximum cutting depth. Different forward models based on interlayer gangue distributions were simulated using finite-difference time-domain algorithms. The results showed a linear correlation between the reflection wave amplitude at the air-coal interface and the rock proportion within the radar detection areas. By analyzing the amplitude variations and corresponding channel numbers, and using a position-matching model based on the uniform movement speed of the antenna, the interlayer gangue distribution parallel to the coal wall is precisely identified. The burial depth of the interlayer gangue in the mining direction was determined with a 6-cm calculation error. Applying this method to identify the interlayer gangue distribution on mining faces yielded an average error of 8.7 cm for distribution and 3.7 cm for burial depth, achieving centimeter-level precision.