Model tests and three-dimensional discrete element numerical simulation on working mechanism of single pile with cap

Based on digital photogrammetry technology, the load transmission characteristic, soil deformation distribution pattern, and mesoscopic structure parameter change rule of sing pile with different cap sizes are studied by visual model test and three-dimensional discrete element numerical simulation method. The study results show that the foundation pile firstly reaches the limit bearing capacity during the initiation of loading, the late bearing capacity of single pile with cap are mainly shared by the soil under cap. The weakening effect on pile bearing capacity and constraint effect on soil lateral deformation caused by cap strengthen gradually as the increase of cap size. The vertical deformation influence scope extends to pile end for single pile with large cap, pile tip soil still shows the deformation mode of cavity expansion. Single pile with small cap presents the punch damage mode, single pile with large cap presents general shear failure mode. The research results have important reference value for the study on working mechanism of other piles. ©, 2015, Editorial Office of China Civil Engineering Journal. All right reserved.