Rules of stress distributions and failure characteristics in inclined coal seam floor due to mining; [倾斜煤层底板采动应力分布规律及破坏特征]

For studying the rules of stress distributions in inclined seam floor under mining, a floor stress solving mechanics model along the seam oblique direction is established based on the semi-infinite body theory of the elastic mechanics and the shear stress and horizontal stress at any points in the inclined seam floor are calculated. Then the features of stress variation and destruction in the floor of 21110 working face in Chensilou coal mine is simulated by using FLAC3D software. The result shows: 1) after the face advancing 90 meters, the vertical stress becomes higher than the horizontal stress in the floor. In the gob areas, the horizontal stress is higher than the vertical stress within 30 meters below the coal seam and its reduction is less than vertical stress within 10 m below the coal seam. 2) when the gob changes to be a square(the length of gob is equal to the width of working face), the vertical stress becomes higher than stress at 10 m behind the working face and its reduction is less than horizontal stress. 3) A site experiment is carried out on the floor of 21110 working face by using the bore hole leak detection device and the maximum damage depth in floor is 16.2 m, which matches with theoretical calcula- tions and numerical simulations. © 2018, Editorial Board of Journal of Mining & Safety Engineering. All right reserved.