DEM analysis on the installation and bearing process of open-ended pile considering plugging effect

The penetration process of open-ended pile would cause complex plugging effect, which further influences the pile installation and bearing characteristics. Considering the high cost、long period and limitations in reflecting the interaction between pile and soil plug of the traditional experimental approach, the jacking installation and subsequent loading process of open-ended pile in sand is simulated based on Discrete Element Method (DEM). The Periodic cell replication method is applied to generate a homogeneous foundation sample with linear stress distribution. Based on the analysis of the soil deformation characteristics, the characteristics of the active arch and passive arch distribution of the soil plug is revealed. Based on the analysis of the evolution of soil plug parameter and plug bearing characteristics, it is found that the incremental filling ratio (IFR) is more sensitive to the plug behavior and the development of plug resistance shows good consistency with the trend of IFR value. Also, the open-ended pile is in the fully plugged mode under static load and the load-displacement response of soil plug is elastic-plastic. Finally, the calculation method of end bearing capacity of open-ended jacked pile is constructed by considering the CPT cone resistance、plugging effect and pile size effect. The above results reveal the evolution process and bearing mechanism of soil plug and could provide some reference value for the prediction of installation resistance and calculation of bearing capacity of open-ended pile considering soil plugging effect.