EXPERIMENTAL STUDY ON CALCULATION OF THE TENSILE STRENGTH OF COAL BASED ON THE SLEEVE FRACTURING METHOD

The tensile strength of coal is one of the most important indexes in the calculation of the width of coal pillar. To achieve tensile strength parameters of coal, the 3# coal seam of Yuanzhuang coal mine was taken as research target. Based on elasticity theory and wave test, sleeve fracturing method was used for testing tensile strength. The results show the wave velocity of coal has an obvious anisotropy and wave velocity in vertical layers level direction is less than the parallel layers level direction. Tensile strength of coal rock by sleeve fracturing is 1.10MPa to 1.70MPa and average value is 1.35MPa. Integrity coefficient of coal was 0.47 and average value of tensile strength of coal seam is 0.63MPa. The research results can provide scientific basis for underground engineering application of tensile strength of coal seam and other low strength rock mass.