Layout study of bottom drainage roadway in deep mining of very close adjacent coal seam group

Based on the engineering background of the ultra-close adjacent coal seam group in the deep part of Pingdingshan No.8 coal mine, this paper studies the reasonable layering of bottom pumping roadway under the mining condition of deep ultra-close seam. FLAC3D numerical model is used to simulate the evolution law of the plastic zone, stress field and displacement field of coal seam under different net rock distances between the roof of bottom pumping roadway and Ⅵ16-17 coal seam. The results show that when the net rock distance is 3 m or 5 m, the coal seam above the bottom drainage roadway can be divided into pressure relief zone, stress concentration zone and primary rock stress zone under the influence of mining. When the net rock distance is 8 m or more, the coal seam above the bottom drainage roadway can be divided into pressure relief zone and primary rock stress zone under the influence of mining. The optimal layout of bottom drainage roadway is 8-10 m distance from the retained net rock. After the bottom