Study on Distribution Law of Loose Circle of Roadway Surrounding Rock in Hard Roof Coal Seam
In order to analyze and study distribution law of loose circle of roadway surrounding rock in hard roof coal seam,taking the actual engineering geological conditions of Yidong Mining Industry in Yushen Mining Area of Northern Shaanxi as the background,through analyzing the formation mechanism of the loose circle of the roadway surrounding rock,and based on the equivalent circle method,the theory of the loose circle of the roadway surrounding rock in the hard roof coal seam is derived and numerical example analyzed using stress balance conditions.The depth of the loose circle of the surrounding rock and the required support strength of the roadway are obtained;Using FLAC3D numerical simulation software,a three-dimensional model of the roof and floor stratum of the roadway is established,and the top of the model is loaded to obtain the stress distribution,deformation situation,and plastic zone distribution law of the roadway surrounding rock.The results show that in the hard roof coal seam roadway,due to the overall downward pressure of the roof in the loose circle above the roadway,the roadway surrounding rock undergoes tensile failure and shear failure,resulting in the transmission of roof pressure to the two sides,causing stress concentration on the two sides compared to the roof and floor;An analysis is conducted on the existing support method,and improved support parameters are proposed according to the theoretical derivation caculation results and numerical simulation rules of the loose circle of roadway surrounding rock.
roadway surrounding rockstresssupport strengthplastic loose circle
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