FEM Simulation of Failure of Reinforced Sand Based on a New Work-Hardening Constitutive Model

To gain a better insight into the failure mechanism of reinforced sand, a FEM simulation of plane strain compression tests of dense Toyoura sand reinforced with planar reinforcement having a wide range of stiffness was performed. A new elastoplastic constitutive model for sand, having a stress path-independent work-hardening parameter based on modified plastic strain energy, is applied. The constitutive model of sand is capable of simulating the effects on the deformation characteristics of stress history, stress path and pressure level, taking into account inherent anisotropy in the elastic and plastic properties and work-softening associated with strain localization into a shear band. The FEM code incorporating the above-mentioned new constitutive model is validated by a direct comparison between results from the physical experiments and the numerical simulation for sand specimens reinforced by using relatively flexible and rigid reinforcement as well as an unreinforced sand specimen. The comparison was made in terms of global stress-strain relationships and local strain fields showing the generation and development of shear band. It was found that the FEM code incorporating the proposed model work-hardening model simulates the experimental results much better than one with the previous shear strain-hardening model.