Numerical Modelling of Laterally Loaded Piles in PLAXIS 3D - A study on embedded pile and soil response in PLAXIS 3D under lateral load

Abstract

Embedded pile element in PLAXIS 3D is an efficient method for pile foundation modelling. The current project provides an overall study on the embedded pile and surrounding soil response in PLAXIS 3D. The finite element models are established, and then analysed and validated using field experiment and theoretical analysis. In the model, the tractions on the pile skin are estimated from skin stiffness. It is found that the axial skin stiffness has a linear relationship with shear stiffness of soil. The lateral skin stiffness has fixed relationship in all models with axial skin stiffness, which is different from software manual information. The pile-soil system subjected to lateral load can be well simulated using the embedded pile by evaluating the pile segment model and single pile model. The surrounding soil state (movement and stress) can be well predicted comparing with the volume pile models. The lateral load-lateral deformation (p-y) curves developed from the models are with good agreement with theoretical analysis on the ultimate soil resistance and deflection. And embedded pile may provide more conservative results than volume pile. The single pile under lateral load has been evaluated using field measurement and theoretical computation, which shows embedded pile is able to provide reliable estimations on the aspects such as deflection along the pile and p-y curve on the ground surface. Meanwhile, embedded pile still has some limitations, such as local capture of the tractions. The axial traction near two tip points is estimated higher than the middle part along the small pile segment. It may also have relatively large limitation for laterally loaded pile group modelling, especially on the load distribution in the group under a given displacement, and on the pile group behaviour with large spacing more than 6 or 7 diameters. The possible reasons could be the pile group uses similar calculation mechanism for axially loaded pile group, which is different from laterally loaded case and leads to the wrong estimation on the back row. Embedded pile is a useful tool for modelling of piled foundations, but it is still a relatively new object in the software with large room for enhancement