DEM investigation of installation responses of jacked open-ended piles

This paper presents a discrete element modelling of the installation responses of rigid open-ended piles with different diameters. A two-dimensional model of granular soil is generated using the particle flow code. The model is generated under 100 g gravity to simulate deep foundations. The simulation results show good agreement with the published experimental measurements. Particle-scale information is retrieved to reveal the micro-mechanics underlying these dynamic behaviours. It is found that relative particle displacement field provides clear micro-scale evidence to the development of shear zones. The instantly fully plugged mode and the partially plugged mode continuously exchange during pile installation, which is more apparent in slimmer pile. Pile base resistance (plug resistance plus annulus resistance) contributes to the majority of pile resistance. The plug resistance is only concentrated within the zone 2-3 times of pile diameter above the pile base. The unit lateral resistance at a specific depth decreases in pile installation. Pile installation causes increases in the average stresses surrounding the pile, with the major influence zone concentrated within six times of pile diameter.