Quantitative study on piled state of collapsed top coal and drawing ratio in longwall with top coal caving

被引：0
|
作者：
Yan S. [1 ]
Shen Y. [1 ]
机构：
[1] School of Energy and Mining Engineering, China University of Mining and Technology-Beijing, Beijing
来源：
Caikuang yu Anquan Gongcheng Xuebao/Journal of Mining and Safety Engineering | 2023年 / 40卷 / 04期
关键词：
breaking angle of top coal; drawing ratio; lagging collapse; long-wall with top-coal caving; piled state of falling top coal;
D O I：
10.13545/j.cnki.jmse.2022.0455
中图分类号：
学科分类号：
摘要：
The main factors affecting the piled state and drawing ratio of top coal caving are the thickness of top coal, the cutting height of shearer, the breaking angle of top coal, the lag caving distance of top coal, and the direct roof caving and piled characteristics. By comparing and analyzing, it is found that the reason for the low release rate of thick hard top coal is the variations in the collapse and pile states of top coal under various combinations of top coal and direct top coal. Based on the caving characteristics of the collapsed top coal under the condition of breaking angle of medium hard coal and hard coal <90°, the motion trajectory is simplified as circular motion and free fall motion, and model of collapsed top coal is established. It is concluded that the caving coal forms a state of “quadrilateral piled state” or “triangle piled state” behind the support. Theoretically, two state-specific parameter formulas are provided, combined with a quantitative formula for top coal drawing ratio. The research shows the piled state of collapsed top coal is determined by the five elements of the piled state of collapsed top coal, and the top coal drawing rate is determined by its pile profile, so it can be obtained that there is a quantitative relationship between the top coal drawing rate and its five elements, which is as follows: The top coal drawing ratio increases logarithmically with the breaking angle of top coal, while decreasing exponentially with the lagging caving distance of top coal and the thickness of top coal; increases exponentially with the cutting height of shearer and the filling angle of waste; decreases exponentially with natural angle of top coal. They provide not only a prediction model for the study of the drawing ratio of thick hard top coal under different mining conditions, but also a theoretical guidance for the selection and effect evaluation of the weakening scheme of thick hard top coal. © 2023 China University of Mining and Technology. All rights reserved.
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页码：656 / 667
页数：11
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