Under the certain strain path

granular materials may exhibit non-localized failure mode corresponding to an abrupt occurrence of failure with the stress states within the Mohr-Coulomb yielding surface. Using the discrete element method（DEM）

mechanical properties of granular material with different rolling friction coefficients are examined under proportional strain loading paths. For particle assemblies of different densities

looser assemblies tend to have diffuse failure

which qualifies Hill’s second-order work criterion. A contact model considering rolling friction is adopted in DEM analysis. By changing the rolling friction coefficient

micro-macro mechanical properties of particle assembly are studied under a specific proportional strain-loading path. The enhancement of particle rolling resistance reduces the likelihood of diffuse failure. At the macro level

stress path changes from strain softening to strain hardening as the rolling friction coefficient increases

and the looser particle assembly exhibits the similar mechanical behaviours as the denser one. The micro-structure shows the corresponding mechanism of action. As the rolling friction coefficient increases

the angular velocities of particles and their distribution will be well controlled. Although the coordination number decreases

the contact forces are enhanced

and the instabilities and anisotropies of the force chain distribution can be improved in the system. All the microscopic parameters manifest a stable structure

which can resist the increasing load

thus the specimen will not form a loose contact state and diffuse failure will not occur.