Abstract：In order to investigate the deep-footing mechanism of reinforced sand，a series of results from plane strain laboratory model test with different number of reinforced layers，are simulated by a nonlinear FEM analysis incorporating an elasto-plastic constitutive model for sand. The constitutive model is developed to have a stress path-independent work-hardening parameter based on the modified plastic strain energy concept. The model ground is made of air-dried dense Toyoura sand，which is either unreinforced or reinforced with numbers of layers and vertical spacing of layers of linear，tensile reinforcing members placed horizontally beneath a strip footing. The results indicate that load-settlement relationships obtained by the FEM analysis are well comparable with those from the physical experiment. It is found out that the peak footing load of reinforced ground increases significantly with the increase of the number of reinforcement layers (the deep-footing effect)，despite that fact the reinforcement length is the same as the footing width，and the contribution by the deep-footing effect is more important than that of the wide-slab effect. In addition，the results also indicate that the progressive failure of model ground with a development of shear bands and the induced tensile forces of reinforcement are reasonably examined by the present FEM analysis，and the deep-footing mechanism of reinforced sandy ground can be well understood.
