Roof Deformation Characteristics and Preventive Techniques Using a Novel Non-Pillar Mining Method of Gob-Side Entry Retaining by Roof Cutting

Yajun Wang, Yubing Gao, Eryu Wang, Manchao He and Jun Yang
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Yajun Wang: State Key Laboratory for Geomechanics & Deep Underground Engineering, China University of Mining & Technology, Beijing 100083, China
Yubing Gao: State Key Laboratory for Geomechanics & Deep Underground Engineering, China University of Mining & Technology, Beijing 100083, China
Eryu Wang: State Key Laboratory for Geomechanics & Deep Underground Engineering, China University of Mining & Technology, Beijing 100083, China
Manchao He: State Key Laboratory for Geomechanics & Deep Underground Engineering, China University of Mining & Technology, Beijing 100083, China
Jun Yang: State Key Laboratory for Geomechanics & Deep Underground Engineering, China University of Mining & Technology, Beijing 100083, China

Energies, 2018, vol. 11, issue 3, 1-17

Abstract: A new non-pillar mining technology, gob-side entry retaining by roof cutting (GERRC), different from the conventional gob-side entry retaining formed by a roadside filling support, is introduced in this study. In the new technology, roof cutting is conducted so that the roof plate forms a short cantilever beam structure within a certain range above the retained entry, thus changing the stress boundary condition of the roof structure. To explore the deformation characteristics of the roof under this special condition, a short cantilever beam mechanical model was established and solved using energy theory and displacement variational methods. Meanwhile, a theoretical and analytical control solution for roof deformation was obtained and verified via field-measured results. Based on the aforementioned calculation, the relationship between the roof deformation and main influence parameters was explored. It was concluded that the rotation of the upper main roof and width of the retained entry had the most significant impacts on roof deformation. Bolt and cable support and temporary support in the entry had a non-obvious influence on the roof deformation and could not prevent the given deformation that was caused by the rotation of the upper main roof. Based on comprehensive theoretical analysis and calculation results, ideas and countermeasures to control short cantilever roof deformation—that is, designing a reasonable height of roof cutting and a controlled width of retaining entry—were proposed and tested. Field monitoring shows that the entry control effects were satisfactory.

Keywords: coal resources; roof cutting and pressure release; non-pillar mining; entry maintenance; surrounding rock control (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2018
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (15)

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