Fast Lagrangian Analysis of Continua（FLAC） is used to model the mechanical behavior and failure process of granular materials under the condition of the compressive displacement-controlled loading.Circular granulae and interfaces between them are divided into squared elements with the same size.Granular elements are seen as isotropic and elastic materials

while interface elements obey a strain-softening and ideal plastic relation beyond the occurrence of failure.After an interface element is completely failed

its cohesion is assigned to be zero and the internal frictional angle is not zero.These assumptions are applicable for simulation of pure friction behavior between granulae.Numerical simulations are conducted in biaxial plane strain compression.Numerical results show that the compressive stresses propagate in the direction of the displacement-controlled loading within the specimen in the form of the compressive stress lines passing through the contact points between granulae.Eventually

clear and ordered compressive stress lines are formed.In some interface elements

shear strain increments are high.It is easy to find the weakest parts of the specimen from the regions with higher shear strain increments.Besides

effects of confining pressure acting on the lateral sides of the specimen

initial cohesion and internal frictional angle of interface elements on the stress-timestep curve are studied.