Multiscale Modelling of Normal Fault Rupture-Soil-Foundation Interaction

Abstract

A multiscale approach that couples the finite element method (FEM) and the discrete element method (DEM) is employed to model and analyses the earthquake fault rupture-soilfoundation interaction (FR-SFI) problem. In the approach, the soil constitutive responses are obtained from DEM solutions of representative volume elements (RVEs) embedded at the FEM integration points so as to effectively bypass the phenomenological hypotheses in conventional FEM simulations. The fault rupture surfaces and shear localization patterns under normal faults with or without foundation atop have been well captured by the multiscale approach and verified with available centrifuge experimental and numerical results. By examining the responses and microstructural evolutions of local RVE packings, it is found that the RVEs located in- or outside the shear bands (SBs) behave distinctly, and may change their stress states from initial at-rest to active in the normal fault case. The micromechanics study also sheds lights on the possible detriment of heavy foundations for the superstructure despite the rupture surface diversion.