Three-component channel wave characteristics and fine imaging of erosion zone

Intelligent mining on working face requires reliable geological guarantee technology. Transmitted channel wave detection is an effective method to detect geological structures in working face. However, three-component channel wave field characteristics of detecting the erosion zone have not been revealed, which results in difficulty in fine imaging of scour zones. In this paper, numerical modeling and field tests were conducted. The results indicate that when seismic source is excited, the body waves propagating along the roof and floor and the channel waves propagating in the coal seam. When the channel wave propagating in the erosion zone and then produces diffraction wave which propagating along the seam behind the erosion zone, and the rest continues to propagate forward. Owing to absence of coal seam in erosion zone, transmitted channel wave is converted to S-wave on entering the erosion zone, therefore the seismic record shows the partial absence of the transmitted channel wave in Event, and the converted S-wave propagates along roof and floor of coal seam, and they are not able to form channel waves with higher energy. Besides, the Y-component of the channel wave is suitable for detecting erosion zone, because it has high amplitude and it can be easily distinguished. The attenuation imaging method based on eigenvalue limitation has high imaging resolution and good abrupt convergence. Three-component transmitted P-wave and S-wave have no obvious response to erosion zone and cannot be used as characteristic waves for the erosion zone detection.