Study on the evolution mechanism of damage to overburden fissures of repetitive mining of close coal seam groups by positive faults.

For the safety of coal mines and the efficient use of gas resources, precise identification of gas transmission routes and enrichment zones is essential. The mining of the coal seam causes many fissures in the overburdened rock, and the evolution of mining fissures is intimately linked to gas transport channels.In order to study the characteristics of overburden fissures in the mining of close coal seam groups under the influence of faults, Shucheng Mining Area in Guizhou as a Research Context, Research using physical similarity simulation tests and numerical simulation methods. The results show that the location of the overburden rupture line interacts with the faults and together they construct a stable inverted triangular overburden stability structure; Given the existence of faults, the upper seam is subjected to greater stress during mining compared to the lower seam, which makes the fissure development process in the upper seam more active.Mining significantly affects the stress distribution of the overlying rock layer of the upper disc coal seam. The stress of the upper disc coal seam increases with the advancement of mining of the lower disc coal seam, and the stress suffered by the side with fewer fault gaps is greater. The results of the study can provide a theoretical basis for mining close coal seam groups in fault tectonic regions, and promote coal mines to achieve safe and efficient use of gas.