Abstract:A contacting constitutive model was established and a biaxial numerical test method on graded broken stone(GBS) was proposed based on particle flow code. Influence laws of the numerical test were studied, and the reliability and practicality of the numerical test were verified. The results show that compared with displacement control mode, the results of the numerical test are more stable than that of strain rate control mode. When the value of loading rate is 0.5%·min-1 and the size of specimen is Φ300 mm×h600 mm, the loading rate and size of specimens have little effect on the results of the numerical test. The deviatoric stress increases linearly with confining stress. Poisson’s ratio has a little effect on the numerical test results. The peak point of deviatoric stress increases linearly with the increase of friction coefficient and shear modulus.