Detection technique and application of transmitted in-seam wave in thin coal seam
【Abstract】Aiming at the problem of serious attenuation of in-seam waves in thin seam and its limited distance of propagation, a method of restricted CT imaging was proposed with the furthest in-seam wave propagation distance. Firstly, the variation of in-seam wave frequency with different thickness of coal seams was studied by theoretical derivation. With a 1.5 m thin seam as the main research object, the attenuation characteristics of in-seam waves were simulated by forward modeling, and the effective propagation distance of in-seam waves was determined. The actual data of No. 15 coal seam in a coal mine in Shandong Province shows that the in-seam wave propagation distance is about 300 m. For the in-seam wave data of Seam 15 in a coal mine in Shandong Province, the fault position interpreted from CT imaging with the technology coincided basically with that exposed by roadway. When processing the in-seam wave data of 1.5 m thick coal seam, with 300 m of propagation distance as the constraint to conduct the energy attenuation imaging on actual data, the in-seam wave CT imaging quality and interpretation accuracy were improved. This method takes into account the propagation characteristics of in-seam waves in thin coal seams, reduces the influence of attenuation, and highlights the anomalies caused by structural factors. It is useful for the development and application of in-seam wave detection technology in thin seams.
【Keywords】 thin coal seam; transmitted in-seam wave; energy attenuation; velocity filtering; fault; CT imaging;
(Translated by ZHANG XY)
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