Based on the theory of particle flow

Particle Flow Code(PFC)model of soil with weak intercalated layer are constituted by adopting the contact-bond model and the slip model. The failure process and strength of sample are studied by PFC numerical simulation to analyze the stress-strain relationship curves of PFC model under different confining pressures and parameters and diagnose the trend of failure via displacement vector fields. The simulation results show that that failure occurs along the weak intercalated layer in the condition of general confining pressures

but in a special confining pressure

failure is not controlled by weak intercalated layer. The peak value of stress-strain relationship curves declines as normal stiffnesses and friction coefficient of weak intercalated layer bring down

the sample will present yielding flow character in the early stage of loading when the friction coefficient approaches 0. The peak value of stress-strain relationship curve declines only when the shear stiffnesses are under a special value. Through analysis

inhesion relations between particle’s micro parameters and macroscopic mechanics actions are gained; and have a further understanding of weak intercalated layer’mechanical properties and progressive failure of soil.