Coupled DEM-FDM investigation of centrifuge acceleration on the response of shallow foundations in soft rocks

The investigation of the response of cemented materials to the installation of rigid foundations is a complex problem due to the presence of material and geometric non-linearities, large deformations and sometimes dynamic conditions. Centrifuge testing is typically employed to carry out laboratory-scale physical models with field-like stress levels. Numerical models such as the discrete element method (DEM) can be used to improve our interpretation of physical models by replicating the laboratory tests virtually, i.e. creating a “digital twin”, and subsequently accessing information which can be difficult or impossible to measure in the laboratory. DEM models of boundary value problems are however challenging and require numerical procedures to reduce the computational burden. In this work, particle upscaling and DEM-FDM (Finite Difference Method) coupling is used to simulate the penetration of a shallow foundation into weakly cemented granular materials under different gravity levels. A fast-generation technique for the preparation of the digital twin, considering the distribution of particle weight is also proposed. The numerical results show that load-displacement curves are very similar to each other, indicating that the failure mechanism at shallow depths is governed by a punch-like mechanism. It is also shown that the punching response is largely influenced by the post peak response of the bonded material.