Volume 8, Issue 5, September 2020, Page: 91-102
Secondary Gob-side Entry Retaining Technology with Double Side Roof Cutting and Pressure Relief in Thin Coal Seam
Luying Shao, State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology, Xuzhou, China
Bingxiang Huang, State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology, Xuzhou, China
Xinglong Zhao, State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology, Xuzhou, China
Received: Aug. 31, 2020;       Accepted: Sep. 14, 2020;       Published: Sep. 23, 2020
DOI: 10.11648/j.ogce.20200805.11      View  110      Downloads  45
Abstract
In order to solve the problems of stress concentration and large deformation of surrounding rock of secondary gob-side entry retaining in thin coal seam caused by hard overhanging roof, the method of cutting off overhanging roof on both sides of roadway by manual pre-cutting seam is adopted. It can transfer high stress to goaf on both sides of roadway and reduce roadway deformation. The mechanism of roadway formation, the conditions of double side overhanging roof subsidence and the stress reduction of roadway side support of secondary gob-side entry retaining after double side roof cutting are given. This paper studies the pressure relief law of secondary gob side entry retaining after double side roof cutting in thin coal seam. After double side roof cutting, the stress of roadway side support is reduced by 76%, the maximum vertical displacement of roof is reduced by 84%, and high stress is transferred to goaf. The influence of different double side roof cutting thickness and angle on the pressure relief effect is analyzed. On the premise that the collapsed gangue can fill the goaf, the smaller the thickness of double side roof cutting is, the better the pressure relief effect is, and the greater the double side roof cutting angle is, the better the pressure relief effect is. It has been successfully applied in the left five roadway of No. 69 coal seam in Xinqiang coal mine, and the deformation of roof and floor is reduced by 47% and the deformation of two sides is reduced by 56% after double side roof cutting. It has important reference value for the future secondary gob-side entry retaining.
Keywords
High Stress, Mining Influence, Double Side Roof Cutting, Secondary Gob-side Entry Retaining, Stress Transfer
To cite this article
Luying Shao, Bingxiang Huang, Xinglong Zhao, Secondary Gob-side Entry Retaining Technology with Double Side Roof Cutting and Pressure Relief in Thin Coal Seam, International Journal of Oil, Gas and Coal Engineering. Vol. 8, No. 5, 2020, pp. 91-102. doi: 10.11648/j.ogce.20200805.11
Copyright
Copyright © 2020 Authors retain the copyright of this article.
This article is an open access article distributed under the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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