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Mathematical Problems in Engineering
Volume 2016, Article ID 4720867, 11 pages
Research Article

Analytical Analysis and Field Observation of Break Line in the Main Roof over the Goaf Edge of Longwall Coal Mines

1College of Resources & Safety Engineering, China University of Mining & Technology (Beijing), Beijing 100083, China
2Shandong University of Science & Technology, Qingdao 266510, China

Received 9 May 2016; Revised 12 June 2016; Accepted 15 September 2016

Academic Editor: Marek Lefik

Copyright © 2016 Zhang Guangchao et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


This paper presents an integrated approach for analytical analysis and field tests to estimate the break line in a main roof over the goaf edge. An analytical model which treated the main roof as a beam seating on the Winkler foundation and subjected to nonuniformity roof loading was established. Further analysis of the bending moment distribution of such a main roof beam was undertaken. Based on the geological conditions pertaining to a case study at Wangjialing coal mine, Shanxi Province, China, the break line in the main roof in a typical longwall panel was calculated in the rib-sides at a distance of 5.6 to 7.4 m from the goaf edge. The influence of main roof flexural rigidity and foundation rigidity and so forth on the bending moment distribution was revealed by a parametric study. Borehole camera detection was employed to further validate the analytical model and its results. The results of the field test demonstrated that the break line detected in the main roof was about 5.5 to 6.8 m away from the goaf edge, which was in good agreement with the analytical model.