Barbara Mazzolai

Earthquake surface fault rupture can cause substantial structural damage and loss of life in near-fault regions. This hazard may be effectively modeled as a large-strain boundary-displacement problem governed by the fundamental granular nature of soil. Tremendous insights into the rupture mechanisms of granular soils are possible when soil is examined as a particulate medium with the characteristics of individual particles modeled numerically with the discrete element method (DEM). In this study, the interaction of a propagating fault rupture surface with a building foundation, called fault rupture-soil-foundation interaction (FR-SFI), is simulated in three dimensions using DEM with irregularly-shaped particles to capture the non-spherical nature of sand grains. High-performance computing simulations of free-field surface fault rupture and FR-SFI are validated against the results of geotechnical centrifuge experiments. Parametric analysis of the effects of soil density, modeled directly with particle assemblages having different void ratios, on FR-SFI is then performed with foundations of different contact pressures at different locations. Through quantitative analyses of inter-particle contact forces, particle rotations, particle displacements, and changes in void ratios, DEM provides insights on particle responses not possible with conventional continuum methods.