Modelling the bearing capacity of displacement piles in sand

Abstract

For complex geotechnical constructions, especially in cases with complex load combinations or strong interaction with neighbouring structures, the use of finite elements is common. One notable exception is the design of driven or soil-displacement piles and the calculation of their bearing capacity. The correct modelling of the pile installation process in finite elements proves to be difficult, whereas the influence on the stresses and the soil properties surrounding the pile is large, and subsequently the influence on the bearing capacity is large. The current study investigates the various pitfalls when attempting to use a standard finite element package for this purpose. To this end, different modelling approaches have been used, and the results have been compared with two model tests of displacement piles installed in flight in a geotechnical centrifuge. A complete modelling of the installation process is still unattainable. However, even without modelling the installation in detail, an acceptable prediction of bearing capacity can be obtained using a well-defined series of modelling steps. An advantage of the modelling approach presented in this study is that the input parameters for the soil need not be calibrated based on a pile load test, but could be obtained from a (more cost-effective) site investigation.