Geometric anisotropy modeling and shear behavior evaluation of graded crushed rocks

To reveal the meso-mechanical mechanism of shear behaviors in the graded crushed rocks (GCRs), which are heterogeneous in geometry and widely used in the flexible pavement, a numerical technique was proposed to simulate the geometric anisotropy of the GCRs using randomly generated models. Then, studies on meso-mechanical responses during the loading were performed through the biaxial shear test and California bearing ratio (CBR) test. The results showed that the changes of both friction and anisotropy had a similar trend with the particle size enlarging in the dense assembly, which maintain stable when the size is less than 3.0 mm. In addition, the breaking sieve (BS) between coarse and fine aggregates was six times of the base diameter (0.8 mm). The predicted shear properties in macrostructure were in good agreement with those laboratory measurements. For the shear behaviors, the fractures and force chains were mainly distributed in the area of action that was limited by force size and side boundary.