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Geomechanics and Engineering
  Volume 22, Number 5, September10 2020 , pages 449-460
DOI: https://doi.org/10.12989/gae.2020.22.5.449
 


A case study on asymmetric deformation mechanism of the reserved roadway under mining influences and its control techniques
Chen Li, Zheng Wu, Wenlong Zhang, Yanhua Sun, Chun Zhu and Xiaohu Zhang

 
Abstract
    The double-lane arrangement model is frequently used in underground coal mines because it is beneficial to improve the mining efficiency of the working face. When the double-lane arrangement is used, the service time of the reserved roadway increases by twice, which causes several difficulties for the maintenance of the roadway. Given the severe non-uniform deformation of the reserved roadway in the Buertai Coal Mine, the stress distribution law in the mining area, the failure characteristics of roadway and the control effect of support resistance (SR) were systematically studied through on-site monitoring, FLAC 3D numerical simulation, mechanical model analysis. The research shows that the deformation and failure of the reserved roadway mainly manifested as asymmetrical roof sag and floor heave in the region behind the working face, and the roof dripping phenomenon occurred in the severe roof sag area. After the coal is mined out, the stress adjustment around goaf will happen to some extent. For example, the magnitude, direction, and confining pressure ratio of the principal stress at different positions will change. Under the influence of high-stress rotation, the plastic zone of the weak surrounding rock is expanded asymmetrically, which finally leads to the asymmetric failure of roadway. The existing roadway support has a limited effect on the control of the stress field and plastic zone, i.e., the anchor cable reinforcement cannot fully control the roadway deformation under given conditions. Based on obtained results, using roadway grouting and advanced hydraulic support during the secondary mining of the panel 22205 is proposed to ensure roadway safety. This study provides a reference for the stability control of roadway with similar geological conditions.
 
Key Words
    reserved roadway; asymmetric deformation; stress distribution; plastic zone; surrounding rock control
 
Address
Chen Li, Zheng Wu and Wenlong Zhang: School of Energy & Mining Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China

Yanhua Sun: School of Civil Engineering, Guizhou University of Engineering Science, Bijie, 551700, China

Chun Zhu: School of Earth Sciences and Engineering, Hohai University, Nanjing, 210098, China

Xiaohu Zhang: 1.)School of Civil Engineering, Guizhou University of Engineering Science, Bijie, 551700, China
2.) State Key Laboratory for Geomechanics & Deep Underground Engineering, Beijing, 100083, China
 

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