Abstract: A series of model tests for reinforced ground were conducted by use of the self-designed model test apparatus,in which the digital photogrammetry for deformation measurement(DPDM) technique was employed and the earth pressure and the footing settlement were measured as well,to investigate the reinforcing mechanism and failure modes of geosynthetic reinforced grounds.Sequential images of the deformation field under a model footing were digitally recorded.The DPDM technique was used to achieve the incremental displacement field and the slip failure surface.It was revealed that the failure surface of non-reinforced ground retained some of the characteristic features of a classical bearing capacity mode of failure,but the reinforcement modified the mechanism to some extent.The mechanism of deformation identified in the tests would constitute a basis for the limit analysis of reinforced grounds.