Rolling resistance is a force couple transferred between two contact particles

which is used for resistance particle mutual rotation. It is an important modification to introduce rolling resistance into discrete element method. In this paper a contact model considering rolling resistance is developed and installed into PFC2D. Using this model

a series numerical model of biaxial shear tests of course-grained soil are carried out to investigate the effects of rolling resistance on the macro- and meso- mechanical responses of particle assemble. The results show that: (1) In macro scope

the shear strength and volumetric response are increased with rolling resistance which is consistent with former researches

and this confirms the validation of the model used in this paper. (2) In meso-scope

the effects of rolling resistance on microstructure of coarse grained soils are investigated; the results show that contact numbers decrease with increasing of rolling resistance; while the shear strength are just to the contrary

that means rolling resistance enhances the stability of force chain network of coarse grained soils. The results show that the contribution of increasing anisotropy with increasing rolling resistance belongs to strong force chain. That confirms that rolling resistance improves the force transmitting ability and resistance of force chain buckling failure of strong force chain. And non-coaxial phenomenon is also observed in this study.