Loose and Broken Distribution of Soft Coal-rock in Deep Coal Roadway Sidewall

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 maintain the stability of deformation of coal roadway sidewalls.