Abstract：In order to study mechanical properties of fractured sandstone, particle flow code ( PFC) software was used to construct the fracture model with different geometric states. The effect of fracture geometry on the mechanical and deformation properties of fracture sample was analyzed. The results showed that compared with complete sample, the peak strength, elastic modulus and peak axial strain of fractured samples were reduced, while Poisson ratio was significantly improved. The peak strength and elastic modulus of fracture samples gradually increased with the increase of rock bridge width, however, along with the increase of rock bridge angle, the elastic modulus of the fractured samples decreased first and then increased. The elastic modulus and peak strength were the minimum when rock bridge angle was same as crack angle. The Poisson ratios of the fractured simples decreased gradually with the increase of width of rock bridge and confining pressure. Along with the increase of confining pressure, the peak strength and peak axial strain of the crack samples increased gradually.The existence of fractures weakened strength characteristics of the specimen and changed deformation characteristics of the samples. The smaller were the rock bridge widths, the stronger was the weakening ability of the sample. Compared with the effects of the width of the rock bridge on the fractured simples, the angle of the rock bridge had less effects on the specimen.

Keyword：fractured sandstone PFC;mechanical property;rock bridge angle;rock bridge width;confining pressure;