Study on overlying stratas movement and stress dynamic evolution aboveworking face in shallow buried 8.8 m extra-thick coal seam

In order to reveal the law of overburden movement and stress evolution during the mining of the 8.8 m extra-thick coal seam mining, the No.12401 fully-mechanized mining face of Shangwan Coal Mine was used as the research background and research and analysis by means of similar simulation experiment, numerical simulation calculation and field measurement to carry out the research and analysis.The results showed that as the working face advances, the maximum and minimum principal stress in the coal seam ahead of mining face are concentrated, and the stress concentration degree increases with the advancement of working face, the maximum main stress concentration and the change of gradient are greater than the minimum principal stress, but the peak leading coal wall range is smaller than the minimum principal stress peak leading coal wall range; the stress recovery phenomenon exists in gob. As the working face advances, the stress recovery degree gradually increases, and the maximum principal stress recovery degree is higher than the minimum principal stress. The large cracks near the working face are closely related to downhole pressure, and relatively large cracks appear on the surface, and the width of cracks near the two channels becomes narrower. There are only caving zones and fracture zones existing in the overlying rock where the bedrock is thinner, and the bending subsidence zone follows changes with the thickness of the bedrock. The study of overlying strata movement and stress evolution law of the 8.8 m extra-thick coal seam can provide guidance value for the development and utilization of extra-thick coal seam resources in Shenfu Dongsheng coalfield and has a broad engineering prospect.