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Failure mechanism analysis on hanging arch roof caving at end of underground coal working face

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Category: Mining

Last Updated on 21 May 2017

Published on 21 May 2017

Hits: 4009

Authors:

B.Y.Hao, College of Mining Engineering, Taiyuan University of Technology, Taiyuan, Shanxi 030024, P.R. China

S.Y.Hu, College of Mining Engineering, Taiyuan University of Technology, Taiyuan, Shanxi 030024, P.R. China

J.Cheng, State Key Laboratory of Coal Resources and Mine safety, China University of Mining & Technology, Xuzhou Jiangsu 221116, P.R. China

H.Huang, College of safety Engineering, Chongqing Vocational Institute of Safety & Technology, Chongqing 404000, P.R. China

K.Wang, College of Mining Engineering, Shanxi Institute of Technology, Yangquan, Shanxi 045000, P.R. China

L.X.Kang, College of Mining Engineering, Taiyuan University of Technology, Taiyuan, Shanxi 030024, P.R. China

Abstract:

Purpose. Understanding the hanging arch distance of the roof in the curved triangle area at the end of an underground coal working face.

Methodology. Using mechanical analysis, we obtain the theoretical maximum roof hanging arch distance in the curved triangle area and expression of supporting pressure borne by protective coal pillars surrounding the curved triangle area. To reflect the results, mathematical derivations are done.

Findings. The mechanical model for roof hanging arch in the curved triangle area at the end of the coal working face is established; the mechanical conditions for the formation of such triangle area is analyzed; the theoretical maximum roof hanging arch distance in the curved triangle area is calculated; the formula showing the corresponding relation between the ineffectiveness of bolt (cable) support of the roadway roof and supporting pressure of coal pillars surrounding the curved triangle area is given as well.

Originality. A series of formulas for the supporting pressure borne by the protective coal pillars surrounding the curved triangle area are derived.

Practical value. If the roof support in the curved triangle area becomes ineffective after completing the corresponding support tasks, both the roof hanging arch distance and supporting pressure of the coal pillars in the triangle area reduce accordingly. These conclusions may supply instructions for designing the width of the protective pillars.

References

1. Kang, H. and Wang, J., 2007. Coal Mine Bolt Support Theory and Packaged Technology, Coal Industry Press.

2. Xiao, T. and Bai, J. 2011. Development Status of High Prestress Bolt Support Theory and Technology. Coal Technology, 30(2), pp. 79‒81.

3. Shao, G., 2009. Technology and Control on First Roof Caving at Fully Mechanized Coal Face with Hard and Massive Roof. Coal Technology, 28(10), pp. 95‒96.

4. Xu, C., 2012. Study on Technology for Controlling Surrounding Rocks in Soft Coal Seam with Great Mining Height Under Complex Geological Conditions. Taiyuan, Taiyuan University of Technology.

5. Yang, P. and Liu, C., 2012. Structure and Reasonable Support Parameters of Basic Roof at the End of Fully Mechanized Caving Face. Mining and Safety Engineering Journal, 29(1), pp. 26‒32.

6. Xiao, Y., 2010. Study on Structural Stability at the End Area of Fully Mechanized Caving Face, 19(2), pp. 83‒88, 103.

7. Xu, Y., 2006. Mining Science. Xuzhou: China Mining University Press.

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