Numerical simulation analysis of flat bottom pile drived into foundation of easily crushable sand

The high-stress level caused by the pile driving can result in grain breakage of sand around the pile, which is more serious for the very easily crushable sand. The grain breakage will lead to the reduction of pile bearing capacity, which can result in the instability of foundation structures even collapse. In this paper, a numerical simulation analysis to investigate the problem of the pile driving into the foundation of very easily crushable sand is performed by adopting a newly developed sand breakage model combining with the Coupled Eulerian-Lagrangian(CEL) method. The model parameters are first calibrated and validated through simulating a series of triaxial tests of Dog's bay carbonate sand. Then, the centrifuge pile driving tests performed on Dog's bay carbonate sand are simulated by using the CEL technique. The simulated results have a good agreement with the experimental measurements, which demonstrates that the adopted breakage model associating with the CEL for solving the pile driving is effective and feasible. All the comparisons indicate that the bearing capacity of the pile is significantly decreased due to the grain breakage. The results are helpful for the design and construction of the pile driving into the foundation of very easily crushable sand.