Study on Numerical Simulation of Overburden Failure Height in Stratified Full-Mechanized Caving of Extremely Thick Coal Seam

In order to determine the failure characteristics of overburden rock under the condition of multi-layer fully mechanized caving mining of soft overburden rock in super thick coal seam, the 1101 working face of Jundong No. 2 Coal mine is taken as the object, the key layer theory and numerical calculation are used to analyze the failure height of overburden rock in the process of regional stratified fully mechanized caving mining, and the relationship between the mining thickness and the failure height of overburden rock is determined. The research shows that the overburden failure height is linearly positive correlated with the mined thickness under the condition of hard overburden in the huge thick coal seam of Jundong No. 2 mining area, and the overburden failure height is 5.3 times of the mined thickness. Failure height of overburden in No. 2 ore in Jundong is much lower than that of common hard overburden.