For open-ended piles of port and harbor foundations, pull-out resistance is not sufficiently taken into account in design. However, in order to develop and improve facilities more efficiently, the pullout capacity needs to be evaluated properly.

To evaluate the pullout resistance of the pile analytically, it is necessary to first understand the changes in mechanical characteristics of the ground during pile driving. Therefore, the continuum analysis using the constitutive law for soils is more suitable than DEM analysis. However, due to the difficulty of performing such numerical computations, ground deformation caused by pile driving has never been successfully simulated. Therefore, in this study, we developed a numerical method that can simulate the ground deformation from pile driving to pulltout.

The material point method (MPM) was used for numerical method, which can track extremely large deformation that cannot be simulated in a commonly-used finite element method due to the distortion of mesh. By considering the frictional contact between pile and ground, we were able to successfully simulate the pile driving process.