Depth-independent cone penetration mechanism by a discrete element method (DEM)-based stress normalization approach

A two-dimensional discrete element model of driven piles in crushable sand was developed and validated against laboratory data. Numerical experiments were conducted to investigate the effects on the pile penetration behavior of initial sample porosity, particle crushability, initial stress state, ratio of pile diameter to median particle diameter, and ratio of model width to pile diameter. A new stress normalization method is adopted to synthesize the data at different driven depths from the simulations. The normalized vertical and horizontal stress fields surrounding the pile show an invariable pattern of stress distribution, suggesting a unique penetration mechanism independent of the penetration depth. The validity of the discrete element method (DEM) simulation results is verified by comparing the stress distributions to those observed from calibration chamber tests on model pile installation in sands.