Overburden Movement Law of Fully Mechanized Top Coal Caving Face in Thick Coal Seam

According to the occurrence condition and mining layout of coal seams, considering the distribution laws of roof cracks and the influence of mining disturbance, this paper comprehensively analyzes the movement laws of overlying strata in fully mechanized caving working face in thick coal seams by means of on-site investigation, rock mechanics experiment and numerical calculation. The results show that the overburden caving develops uniformly from the center of the goaf to all sides under the action of gravity, and the tensile stress zone of the rock stratum presents U-shaped failure distribution under the action of tensile stress. With the extension of tunneling depth and level, the roof failure zone of the working face is hinged with each other to form a stable structure, which hinders the roof movement. The pressure step distance of the working face is larger, the magnitude of overburden caving and rock burst load is larger, and the overburden movement in the middle and upper part of the working face is larger than that in the lower part.