Influence of coal mining subsidence cracks on soil surface watercontent in Shennan Mining Area

In order to explore the influence of coal mining subsidence cracks on soil surface water content (0～20cm) in the western sandy area, a working face in Shennan Ningtiaota coal mine was taken as the study area, and the dynamic cracks and ground fissures of different widths were investigated by TDR. The results show that:① During the entire development period of dynamic fractures, the surface water content around the fracture decreases rapidly at first and then increases slowly, and the loss of water content on the lower side is less than that on the upper side, and the water content and water content recovery rate on the lower side of the crack are slightly higher than those on the upper side. The soil water content on the upper side of the crack is affected within 85 cm with a period of 13 days, and the soil water content on the lower side of the crack is affected within 55 cm with a period of 12 d, and the soil water content on the lower side of the crack is slightly faster than that on the upper side of the crack, under the action of soil self-repair, the soil water content can be basically restored; ② under the conditions of different widths (2,5,9,13,17,24,32,35,38 mm) soil water content was compared and analyzed, and it was found that 2 and 5 mm wide cracks had no significant effect on soil water content. In cracks of 9 mm and above, when the crack[LM]width is the same, the farther away from the crack location, the higher the soil water content; when the distance from the crack is equal, the larger the crack width, the lower the soil water content.