Bored and screwed piles, continuum and discontinuum approaches

The efficiency of piling methods, where soil is retrieved and methods that make use of soil displacement during drilling, results from the interaction between the performance of drilling equipment and the modifications created by the drilling process to soil characteristics. However, little is known yet on what is really happening during the installation of a pile. In Distinct Element models the soil is modelled by an assembly of particles where every single particle is interacting with neighbours by normal and shear forces as well as by transmitting moments. Every single particle can lose contact with neighbouring particles and form new contacts depending on forces acting on the particle and its environment. From the theoretical point of view many aspects of pile installation could therefore be modelled more accurate by using the 3D Distinct Element Method (DEM) than by approaches based on the Finite Element Method (FEM). Both methods have been used exemplarily in the following to assess their capabilities and limitations to simulate pile installation and pile performance.