Research on the failure law and actual measurement of floor in extremely close distance thick coal seam mining.

The vigorous mining of domestic coal resources is accompanied by the complexity and diversification of the conditions of coal seams. Multi seam and close distance coal seam mining have become normalized. For research on the failure law and actual measurement of floor in extremely close distance thick coal seam mining, the paper takes the 30,507 working face of Tashan Coal Mine of China Coal Datong Energy Co., Ltd (Xiaotashan Coal Mine) as the background, obtains the characteristics and scope of the floor failure of the coal seams in the working face through theoretical analysis and numerical calculation, and uses the single hole (Direct Current) DC floor detection technology to carry out on-site measurement. Research has shown that due to the repeated disturbance effects of multilayer coal mining, the lower coal seam floor is prematurely damaged, with a large impact range, and the theoretical characteristics of the overall "lower three zones" of the floor are obvious; The measured maximum damage depth is 16.1 m, and it tends to stabilize within a range of 16 m behind the working face. Single-hole DC detection technology exhibits reliability and accuracy for detecting the damage of coal seam mining floor under complex geological conditions, and this study provides some guidance for the control and detection of rock strata at the bottom of coal seam mining under different geological conditions.