Abstract:In order to more deeply analyze the law of overburden movement under repeated mining of shallow coal seam, the UDEC digital simulation method is used to conduct the simulated mining of the 1# and 2# seams of a certain coal mine in Shanxi Province; finally, the laws of overburden movement and fissure evolution under repeated mining of shallow coal seam are obtained, which is verified by means of two-dimensional physical similarity simulation test. The results show that after the 1# coal seam is mined, the working face first weighting step distance is 30m, for each excavation of approximate 10m, a periodic weighting is formed and the step distance of periodic weighting is 10m; similarly, after the 2# coal seam is mined, the working face first weighting step distance is 40m, for each excavation of approximate 10m, a periodic weighting is formed and the step distance of periodic weighting is 10m. It can be seen that the step distance of the first weighting of the working face of 2# coal seam is larger than that of the working face of 1# coal seam; after the mining of 1# coal seam is completed, the maximum displacement of the direct roof of 1# coal seam is 1.6m, the fissure zone is about 20m high and the roof-fall zone is about 5m; after the mining of 2# coal seam is completed, the maximum displacement of the direct roof of 1# coal seam is 3.2m, the maximum displacement of the direct roof of 2# coal seam is 1.8m, the fissure zone is about 73.5m high and the roof-fall zone is about 15m.
