Abstract： Taking the hard roof with Yeqing limestone as the research subject and aiming at the problem of the initial and periodic weighting step distance and the strength of the weighting, the key strata theory and empirical method are used to calculate the height of the hard roof caving zone. By constructing a bending thin plate model of the hard roof, a finite element model of different working face advancing distances and uniform roof loads is established. Using two types of boundary conditions, e.g., four-side fixed boundary and three-side fixed and one-side free, the fracture limit span and roof sinking of the hard roof are simulated and calculated. The results show that the initial weighting step distance of hard roof ranges from 42 m to 69 m using the thin plate model with boundary condition of four-side fixed; the period weighting step distance of hard roof ranges from 17 m to 29 m using the thin plate model with boundary condition of three-side fixed and one-side free. The simulation results are in good agreement with field data. During the period of initial weighting, firstly, the hard strata damaged from the two ends and then developed toward the center. The maximum sinking position is at the center of the hard roof, and finally, an "O-shaped " fracture is formed; during the period of periodic weighting, the maximum sinking position is in the middle of the hard roof on one side of the stope, and finally, a "C-shaped" fracture is formed.
贾永杰. 野青灰岩坚硬顶板工作面来压步距与强度预测分析[J]. 煤炭与化工, 2022, 45(12): 1-7，11..
Jia Yongjie. Prediction and analysis of pressure step and strength for Yeqing limestone hard roof. CCI, 2022, 45(12): 1-7，11..
