Study on roof failure characteristics of roadway under non-uniform stress

In view of the non-uniform stress during excavation process in the return air roadway of Hongqingliang Mine, the roof has problems such as roof bench convergence and local caving,the geological radar was used to detect the range of surrounding rock loose range, and the discrete element software was used to simulate on lateral pressure change of roadway. The effects of non-uniform stress on the surrounding rock stress distribution and deformation characteristics of the roadway were studied, and the roadway support countermeasures for the surrounding rock conditions were proposed. The results show that surrounding rock failure range is asymmetrical in main return air roadway due to the non-uniform distribution of ground stress. The range of roof, south and north gang loose ranges are 1.7, 2.0 and 1.2 m respectively. The stability decreases as the range of loose ranges increases; under the action of non-uniform stress, the two roadway-sides of roof show the non-uniform settlement, the vertical displacement and stress peak near faults increase obviously, the failure depth and average width increase by 150% and 117% respectively; moreover, the roof falling is advanced and its range is expanded, the duration of deformation and failure also increases.