EFFECT OF GRAIN COMPOSITION ON STRENGTH AND DEFORMATION BEHAVIOR OF COAL GANGUE

According to the well degree of grain composition and coarse grained content, four groups of grain composition were designed, and using triaxial tests, the strength and deformation characteristics of coal gangue with different grain composition were analyzed. The results reveal that, for coal gangue with different grain composition, the deviatoric stress is increasing with the increase of confining pressure and strain. The stress-strain curves have no peak and belong to strain hardening. When the grain composition is well, the distributions of peak strength with coefficient of curvature(Cc) and non-uniformity coefficient(Cu) are all parabolas, which are decreasing firstly then decreasing. While the grain composition becomes poor, the peak strength is decreasing gradually. The cohesive force is increasing with the decrease of coarse grained content, and its value is controlled by fine particles. The internal friction angle is not only affected by the content of coarse grain but also is associated with the well of grain composition.