Study on analogue experiment on hydrogeological effect and localization of hidden water hazard source in coal seam floor

Concealed water-conducting collapse columns and fault water inrush from the coal seam floor frequently cause mines flooding and death disasters in North China coal field. In order to study the various effects of hazard sources in the floor aquifer and the location technology of hidden water hazard sources in the floor, an experimental study of the sand trough was carried out according to the hydrogeological conditions of the C-P coalfield in North China. Experiments show that after the flow field is stabilized, the collapse column effect in the survey area is represented as a closed circle with concentric contours of water head, water temperature and concentration, and the danger source is located in the closed circle of the largest contour; the effect of the faults in the survey area shows that the contour lines of the water head, water temperature and concentration are all parallel lines, and the hazard source is located between the two maximum parallel lines. The maximum temperature and concentration of the two hazard sources are far greater than the range of the water head or the actual size of the hazard sources, the actual locations are close to the side of the density of the contour lines. It is found that regardless of the type of hazard source, the water head contours are sparse in the direction of upstream water flow and and dense in the direction of the downstream flow, the isolines of temperature and concentration are dense in the direction of the downstream flow and sparse in the direction of the upstream flow. When the hazard source is located outside the survey area, the density of the contour lines in the area close to the hazard source is large, and the density of the contour lines in the area far from the hazard source becomes smaller and the trend changes greatly. The effects of the two hazard sources outside the survey area are similar and difficult to distinguish. According to the experimental results, this paper studies two methods of locating hazard sources: the graphic method and the contour fitting method. For the hazard sources in the survey area, the graphic method and the fitting method can be used to locate the danger source, the area of the dangerous source is delineated through the maximum contour area, and the minimum error location is obtained after trial calculation. For the hazard sources outside the survey area, only the direction of its existence can only be determined by graphic method.