Resolution and Analysis on Failure Depth of Face End Floor in Coal Mining Face

in order to understand the three main stress mechanics logic relationship in the main stress field of the floor strata at the face end, the floor failure depth of the face end floor was studied.With the mechanics analysis, the certain mode of the main stress in the face end floor strata was determined.Based on the circumstan ce, the calculation formula of the failure depth at the face end floor was derived.The study results showed that the main stress field under the polar coordinates would b e the polar diameter r and polar angle θ function and the three main stresses would be related to the Poisson ratio μ of the face end floor strata.When the Poisson ratio μ of the face floor strata and the element unit under the polar angle θ of polar coordinates in the face end floor strata could meet the different numerical relationship, th e three main stresses would be different and the calculation formula of the failure depth at the face end floor would be absolutely different.