Loose and Broken Distribution of Soft Coal-rock in Deep Coal Roadway Sidewall
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ORIGINAL PAPER
Loose and Broken Distribution of Soft Coal-rock in Deep Coal Roadway Sidewall De-yi Wu . Sheng Qin
Received: 22 July 2019 / Accepted: 2 May 2020 Ó Springer Nature Switzerland AG 2020
Abstract A FLAC3D numerical model was established on the basis of the coal occurrence conditions of the pedestrian preparatory workings in the central mining block (Area 11–2) of Kouzidong Mine, Huainan, Anhui province, China. The distribution of displacement fields of coal roadway sidewalls was analyzed. The displacement gradient between the line connecting a location of the coal rock at the deep coal roadway wall to the roadway center was used to characterize the bulking conditions of the sidewall and the loose and broken distribution of soft coal rock in the sidewall was obtained. When the depth of a typical roadway ranged from 750 to 880 m, loose and broken coal rocks were distributed widely along the deep coal roadway sidewall, especially in the middle and upper part, with a scope of about 5.0 to 6.0 m. Bulking occurred largely in the middle and lower part of the roadway sidewall. This study will provide a basis for the selection of appropriate support materials to
D. Wu S. Qin (&) National and Local Joint Engineering Laboratory of Building Health Monitoring and Disaster Prevention Technology, Anhui Jianzhu University, Hefei 230022, Anhui, China e-mail: [email protected] D. Wu S. Qin Anhui Key Laboratory of Building Structure and Underground Engineering, Anhui Jianzhu University, Hefei 230022, Anhui, China
maintain the stability of deformation of coal roadway sidewalls. Keywords Deep coal roadway sidewall Displacement gradient of coal-rock Bulking degree Loose-broken rock distribution
1 Introduction As the coal mining depth increases, deformation of the deep coal roadway sidewalls is exacerbated because of the high stress (Shan et al. 2013; Xue et al. 2016; Xie et al. 2018; Xiao et al. 2014; Wang et al. 2018; Guo et al. 2017; Lu et al. 2014). The broken and loosening zone, plastic softening zone, plastic hardening zone and elastic zone (Lu et al. 2014; Song et al. 2006; Xue et al. 2017) successively form in the surrounding rocks after the roadway excavation commences, and the sidewall stability is mainly dependent on the bulking characteristics of the coal rock inside the brokenloosening zone (Huang et al. 2013). The accurate determination of the scope of the broken-loosening zone, the bulking degree, and the distribution characteristics of coal rocks at deep coal roadway sidewall can provide a basis for the selection of appropriate support materials (Guo et al. 2017; Hu and Cheng 2014; Huang et al. 2013). Some studies have previously examined the bulking scope (Kong and Wang 2014; Chang and Xie
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Geotech Geol Eng
2011; Yang et al. 2012; Jia et al. 2014), deformation and damage of surrounding rocks in the deep coal roadway via theoretical analysis, numerical simulation and engineering measurements (Niu et al. 2014; Kang et al. 2007; Zhu et al.
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